Quad 44 pre-amp. Minor restoration, and some sensible modifications

Along with the FM tuner I got last week, I also obtained a matching 44 pre-amp and a 405-2 power amplifier. Very nice kit!

The 44 is a very interesting pre-amp. It's got a lovely design of tone control. Quad went their own way with adding tone controls, and made theirs with 3 tone filters and an adjustable slope control.

The look of the thing is even unique.


The pre-amp has a flexible card system. Each input is selected by a CD4066 switch, which connects the selected card. This unit has the standard line-up of "Radio", "Disc" for a Moving magnet cartridge (an MC card is/was available), a CD/AUX card and two tape loops. Excellent.




Not only that, but the Disc card allows differing gains to be selected to accommodate for most carts, and switchable capacitance load too. The tape loops are similarly configurable for level and impedance. Nice....












This later "MKII" model has a re-designed main board and ALPS pots....










Issues....

CD4066? Known for introducing distortion into the signal path. Thankfully Maxim produce the MAX4066. A much better specified, and pin for pin compatible device....

So, before I start, let's make a baseline measurement of THD (Total harmonic distortion) at 1KHz....  0.059% on the CD/AUX channel.

Not too shabby....







Out with the old, and in with the new....

All 4 ICs are changed.








Whilst I'm in there I evict the Red electrolytics, as they're know to fail, although these all read OK.

Let's have a look at the disc card...

It consists of TL071 op-amps.... which are mediocre. I'll swap them out for some better NE5534, which should lower noise a bit, as well as distortion. These are the better NE5534's with 18V/uS slew rate.







... and here is the main issue for me....

The CD/Aux card....

300mV? ... 300mV!!!!

Since when?

Most CD players put out at least a volt...

All this means practically, is we'll need to turn our volume control down everytime we switch to CD. An inconvenience. We *may* overload the input.

I've seen some CD players output as much as 2V, so 300mV is not going to cut it....

It's also originally fitted with a TL072, which I'll change for an NE5532..

I do some googling, and there's various recommendations about changing the resistors in the feedback loop of the card to reduce the gain to unity... but none of the modifications seem to  relate to the input card I have fitted, an M12815:1. I don't have a schematic, so I sketch one out....

... well, it's already a unity-gain amplifier!

So, what to do? I could trace the signal through and change the gain on the main board, but that will leave me with the same discrepancy when switching between CD and disc or radio.... Nothing for it but to add a bit of attenuation in.


Simply adding a 180 ohm resistor across the existing 820 ohm resistor will divide the voltage down to a more respectable level.





... and it's easy to implement...

Don't forget to do both channels.













So after all out mods... how does it measure?

... The THD has dropped to 0.014%....


How does it sound? Noticeably quieter (noise-wise!), but to my cloth ears, I can't really tell much difference in the distortion.

Right, now to the 405-2 Power amp!

Watch this space....

Quad FM4 drifting and amnesia.

So here it is, the wonderful Quad FM4 tuner. A thing of beauty.

This one is an early example and dates from around 1982-83.

It's suffering from amnesia (it won't store stations after a power off) and even in manual tuning the frequency falls after a few minutes use....

Let's see what's wrong...


It's a simple layout. First off the memory battery is shot, and leaking. Thankfully it hasn't damaged the board, and a replacement (Varta Mempac 4.8V, 150mAH) restores it's memory... as for the frequency drift...

The tuner operates by a voltage controlled tuner, there's no synthesiser in here! The memories work by digitising the tuning voltage and storing it, recreating it with a DAC when the preset is selected. The fault is the tuning voltage is falling off. Turns out it's our best friend (and foe!) the elctrolytic capacitor. The guily parties are all 100uF 6.3V types. I changed them all. I dislike 6.3V electrolytics, they seem to give more problems than higher voltage types, even though they were all working well within voltage limits. Perhaps it's their physical size that makes manufacture difficult? ....  (perhaps they just don't like me?!)

Zoom in on the picture and you can see where they are physically leaking.

This cured the drift, but one of the 220uF 16V caps that smoothes the regulated 12V supply looked like it had seen better days, so I changed both of those too... even though they measured OK. One is adjacent to the 12V regulator transistor, which runs a little hot. Never an ideal location for an electrolytic!


Sound quality is great, and will give many years of service now!

Nakamichi RX-202E

This arrived in the workshop.

It's a Nakamichi RX-202E Unidirectional Auto-reverse cassette recorder. A thing of rare beauty and quality. I must say the quality of reproduction on this unit, knocks the Pioneer CT-F1250 we looked at earlier in the year into a cocked hat, but it is substantially younger!

It unidirectional, because the tape only ever travels in one direction, so no need for two capstans, two pinch rollers, and a complicated and compromised head which will play both sides of the cassette or a complicated mechanism to rotate the head.

Oh no, this uses a complicated mechanism to remove the cassette from the transport and turn it over!

A video is worth a thousand words....



All this machine wanted was a service, and a repair to the position sensor pot.

Arduino Astronomical Clock (and pond pump controller) - now with master clock update!

Well, the DS1307 clock module has a tendency to drift about a bit on my Pond pump controller. It can lose a few minutes each month. Irritating at best.

Now the GPS master clock as been created, it should be fairly easy to synchronise the DS1307 with the 433MHz data from the master clock.

The receiver hardware is connected to 5 volts, GND and it's data line is connected to pin 9 of the Arduino. The antenna is simply 17cm of stiff wire.

Once again, the wonderful Virtualwire library is used, and we simply call the receiver routine (remoteClockSet) in the main loop to see if any data has been received. If it has, update the DS1307, and recalculate the sun rise and set times.

There's a few more variables to declare to deal with the incoming time, and, to be honest the whole thing was written a while ago, and is now horribly un-weildy, and could do with a damn good tidy up and re-write, but it works.

No more difting clock!

Here's the code.


// Dawn & Dusk controller with frost protection. // (C) A.G.Doswell 2014 - 2016 // // Date and time functions using a DS1307 RTC connected via I2C and Wire lib // // Designed to control a relay connected to pin A3. Pin goes low during daylight hours and high during night. Relay uses active low, so is // "On" during the day. This is connected to the fountain pump in my garden. // // Time is set using a rotary encoder with integral push button. The Encoder is connected to interrupt pins D2 & D3 (and GND), // and the push button to pin analogue 0 (and GND) // The RTC is connections are: Analogue pin 4 to SDA. Connect analogue pin 5 to SCL. // A 2 x 16 LCD display is connected as follows (NOTE. This is NOT conventional, as interrupt pins are required for the encoder) // Arduino LCD // D4 DB7 // D5 DB6 // D6 DB5 // D7 DB4 // D12 RS // D13 E // // In this revision, there is a Dallas 18B20 Temperature sensor connected to pin 8, enabling frost protection. This is pulled up to +5volts via a 4.7K resistor. // // Use: Pressing and holding the button will enter the clock set mode (on release of the button). Clock is set using the rotary encoder. // The clock must be set to UTC. // Pressing and releasing the button quickly will display the current sun rise and sun set times. Pressing the button again will enter the mode select menu. // Modes are AUTO: On when the sun rises, off when it sets. // AUTO EXTEND : same as above but goes off 1 hour after sunet (nice for summer evenings!) // ON: Permanently ON // OFF: Permanently OFF (Who'd have guessed it?) // // Change the LATTITUDE and LONGITUDE constant to your location. // Use the address finder from http://www.hacktronics.com/Tutorials/arduino-1-wire-address-finder.html to find the address of your temperature sensor and enter it where required in DeviceAddress. // 28th Dec 2014 - Slowed the rate at which the temperature is requested down to once per minute. It has improved the clock display, and solved an issue whereby the temp sensor wasn't always ready to send data, and hung up. // 10th Jan 2015 - Altered the method of updating the temp to something simpler and more sensible! // 17th April 2015 - Stored Mode settings in EEPROM // 3rd Sept 2016 - Updated to run with 433MHz master clock updates. // // // Be sure to visit my website at http://andydoz.blogspot.com #include <Wire.h> #include "RTClib.h" // from https://github.com/adafruit/RTClib #include <LiquidCrystal.h> #include <Encoder.h> // from http://www.pjrc.com/teensy/td_libs_Encoder.html #include <TimeLord.h> // from http://swfltek.com/arduino/timelord.html. When adding it to your IDE, rename the file, removing the "-depreciated" #include <OneWire.h> // from http://playground.arduino.cc/Learning/OneWire #include <DallasTemperature.h> // from http://www.hacktronics.com/code/DallasTemperature.zip. When adding this to your IDE, ensure the .h and .cpp files are in the top directory of the library. #include <EEPROM.h> #define ONE_WIRE_BUS 8 // Data wire from temp sensor is plugged into pin 8 on the Arduino OneWire oneWire(ONE_WIRE_BUS); // Setup a oneWire instance to communicate with any OneWire devices DeviceAddress outsideThermometer = { 0x28, 0x1A, 0x1A, 0x3E, 0x06, 0x00, 0x00, 0xC7 }; // use the address finder from http://www.hacktronics.com/Tutorials/arduino-1-wire-address-finder.html to find the address of your device. RTC_DS1307 RTC; // Tells the RTC library that we're using a DS1307 RTC Encoder knob(2, 3); //encoder connected to pins 2 and 3 (and ground) LiquidCrystal lcd(12, 13, 7, 6, 5, 4); // I used an odd pin combination because I need pin 2 and 3 for the interrupts. //the variables provide the holding values for the set clock routine int setyeartemp; int setmonthtemp; int setdaytemp; int sethourstemp; int setminstemp; int setsecs = 0; int maxday; // maximum number of days in the given month int TimeMins = 0; // number of seconds since midnight int TimerMode = 2; //mode 0=Off 1=On 2=Auto int TimeOut = 10; int TimeOutCounter; // These variables are for the push button routine int buttonstate = 0; //flag to see if the button has been pressed, used internal on the subroutine only int pushlengthset = 3000; // value for a long push in mS int pushlength = pushlengthset; // set default pushlength int pushstart = 0;// sets default push value for the button going low int pushstop = 0;// sets the default value for when the button goes back high int knobval; // value for the rotation of the knob boolean buttonflag = false; // default value for the button flag float tempC; // Temperature // Over-Ride feature flag for Raminda Subhashana boolean OverRideFlag = false; const int TIMEZONE = 0; //UTC const float LATITUDE = 51.000, LONGITUDE = 2.000; // set YOUR position here int Sunrise, Sunset; //sunrise and sunset expressed as minute of day (0-1439) TimeLord myLord; // TimeLord Object, Global variable byte sunTime[] = {0, 0, 0, 1, 1, 13}; // 17 Oct 2013 int SunriseHour, SunriseMin, SunsetHour, SunsetMin; //Variables used to make a decent display of our sunset and sunrise time. DallasTemperature sensors(&oneWire); // Pass our oneWire reference to Dallas Temperature. #include <VirtualWire.h> // set up virtual wire for connection to 433MHZ Rx. #include <VirtualWire_Config.h> // set up integers for remote master clock int TX_ID = 1; int Hours; int Mins; int Secs; int Day; int Month; int Year; boolean Output; char buffer[5]; void setup () { //Serial.begin(57600); //start debug serial interface Wire.begin(); //start I2C interface RTC.begin(); //start RTC interface lcd.begin(16, 2); //Start LCD (defined as 16 x 2 characters) lcd.clear(); pinMode(A0, INPUT); //push button on encoder connected to A0 (and GND) digitalWrite(A0, HIGH); //Pull A0 high pinMode(A1, INPUT); // Over ride push button connected to A1 (and GND) digitalWrite(A1, HIGH); pinMode(A3, OUTPUT); //Relay connected to A3 digitalWrite (A3, HIGH); //sets relay off (default condition) sensors.begin(); sensors.setResolution(outsideThermometer, 12); // set the resolution to 12 bits (why not?!) //Checks to see if the RTC is runnning, and if not, sets the time to the time this sketch was compiled, also sets default mode to 2 and writes to EEPROM lcd.clear(); lcd.print("Waiting for RTC"); delay (3000);// wait a few seconds for the RTC to sort itself out. DateTime now = RTC.now(); if (! RTC.isrunning()) { RTC.adjust(DateTime(__DATE__, __TIME__)); EEPROM.update (0, 2); // set the auto mode as 2 (auto) for default } vw_set_tx_pin(10); // Even though it's not used, we'll define it so the default doesn't interfere with the LCD library. vw_set_rx_pin(9); // RX pin set to pin 9 vw_setup(1200); //sets virtualwire for a tx rate of 300 bits per second, nice and slow! vw_rx_start(); lcd.print("Dawn Dusk Pond"); lcd.setCursor(0, 1); lcd.print("Pump Controller"); delay (2000); lcd.clear(); lcd.print("Version 1.37"); lcd.setCursor(0, 1); lcd.print("(C) A.G.Doswell "); delay (5000); lcd.clear(); //Timelord initialisation myLord.TimeZone(TIMEZONE * 60); myLord.Position(LATITUDE, LONGITUDE); CalcSun (); TimerMode = EEPROM.read (0); // Read TimerMode from EEPROM delay (1000); } void printTemperature(DeviceAddress deviceAddress) { lcd.setCursor (9, 1); tempC = sensors.getTempC(deviceAddress); if (tempC == -127.00) { lcd.print("Err"); } else { lcd.print(tempC); lcd.print((char)0xDF); lcd.print("C "); } } void loop () { remoteClockSet (); DateTime now = RTC.now(); //get time from RTC //Display current time lcd.setCursor (0, 0); lcd.print(now.day(), DEC); lcd.print('/'); lcd.print(now.month()); lcd.print('/'); lcd.print(now.year(), DEC); lcd.print(" "); lcd.setCursor (0, 1); lcd.print(now.hour(), DEC); lcd.print(':'); if (now.minute() < 10) { lcd.print("0"); } lcd.print(now.minute(), DEC); lcd.print(':'); if (now.second() < 10) { lcd.print("0"); } lcd.print(now.second()); lcd.print(" "); //current time in minutes since midnight (used to check against sunrise/sunset easily) TimeMins = (now.hour() * 60) + now.minute(); //Get and display temp every minute if (now.second() == 7) { sensors.requestTemperatures(); // Request temperature delay (249); printTemperature(outsideThermometer); // display on lcd. } // Calculate sun times once a day at a minute past midnight if (TimeMins == 1) { lcd.clear(); CalcSun (); } // Reset Override flag if the sun is up! if (TimeMins == Sunrise) { OverRideFlag = false; } if (TimerMode == 2) { if (TimeMins >= Sunrise && TimeMins <= Sunset - 1 && tempC >= 2 && OverRideFlag == false) { //If it's after sunrise and before sunset, and it's not frozen, and our override isn't set, switch our relay on digitalWrite (A3, LOW); lcd.setCursor (13, 0); lcd.print ("On "); } else { //otherwise switch it off digitalWrite (A3, HIGH); lcd.setCursor (13, 0); lcd.print ("Off"); } } if (TimerMode == 3) { if (TimeMins >= Sunrise && TimeMins <= Sunset + 60 && tempC >= 2 && OverRideFlag == false) { //If it's after sunrise and before sunset + 1 hour, and it's not frozen, and our override isn't set, switch our relay on digitalWrite (A3, LOW); lcd.setCursor (13, 0); lcd.print ("On "); } else { //otherwise switch it off digitalWrite (A3, HIGH); lcd.setCursor (13, 0); lcd.print ("Off"); } } if (TimerMode == 0) { // Off digitalWrite (A3, HIGH); lcd.setCursor (13, 0); lcd.print ("Off"); } if (TimerMode == 1 && tempC >= 2) { // TimerMode is On, but it's not frozen digitalWrite (A3, LOW); lcd.setCursor (13, 0); lcd.print ("On "); } buttonstate = digitalRead(A1);// check to see if our override button is pressed, if it is, set the flag if (buttonstate == LOW ) { OverRideFlag = true; } pushlength = pushlengthset; pushlength = getpushlength (); delay (10); if (pushlength < pushlengthset) { lcd.clear (); ShortPush (); lcd.clear (); } //This runs the setclock routine if the knob is pushed for a long time if (pushlength > pushlengthset) { lcd.clear(); DateTime now = RTC.now(); setyeartemp = now.year(), DEC; setmonthtemp = now.month(), DEC; setdaytemp = now.day(), DEC; sethourstemp = now.hour(), DEC; setminstemp = now.minute(), DEC; setclock(); pushlength = pushlengthset; }; } //sets the clock void setclock () { setyear (); lcd.clear (); setmonth (); lcd.clear (); setday (); lcd.clear (); sethours (); lcd.clear (); setmins (); lcd.clear(); RTC.adjust(DateTime(setyeartemp, setmonthtemp, setdaytemp, sethourstemp, setminstemp, setsecs)); //set the DS1307 RTC CalcSun (); //refresh the sunrise and sunset times delay (1000); } // subroutine to return the length of the button push. int getpushlength () { buttonstate = digitalRead(A0); if (buttonstate == LOW && buttonflag == false) { pushstart = millis(); buttonflag = true; }; if (buttonstate == HIGH && buttonflag == true) { pushstop = millis (); pushlength = pushstop - pushstart; buttonflag = false; }; return pushlength; } // The following subroutines set the individual clock parameters int setyear () { lcd.setCursor (0, 0); lcd.print ("Set Year"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { return setyeartemp; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { //bit of software de-bounce knobval = -1; } if (knobval > 1) { knobval = 1; } setyeartemp = setyeartemp + knobval; if (setyeartemp < 2014) { //Year can't be older than currently, it's not a time machine. setyeartemp = 2014; } lcd.print (setyeartemp); lcd.print(" "); setyear(); } int setmonth () { lcd.setCursor (0, 0); lcd.print ("Set Month"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { return setmonthtemp; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { knobval = -1; } if (knobval > 1) { knobval = 1; } setmonthtemp = setmonthtemp + knobval; if (setmonthtemp < 1) {// month must be between 1 and 12 setmonthtemp = 1; } if (setmonthtemp > 12) { setmonthtemp = 12; } lcd.print (setmonthtemp); lcd.print(" "); setmonth(); } int setday () { if (setmonthtemp == 4 || setmonthtemp == 5 || setmonthtemp == 9 || setmonthtemp == 11) { //30 days hath September, April June and November maxday = 30; } else { maxday = 31; //... all the others have 31 } if (setmonthtemp == 2 && setyeartemp % 4 == 0) { //... Except February alone, and that has 28 days clear, and 29 in a leap year. maxday = 29; } if (setmonthtemp == 2 && setyeartemp % 4 != 0) { maxday = 28; } lcd.setCursor (0, 0); lcd.print ("Set Day"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { return setdaytemp; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { knobval = -1; } if (knobval > 1) { knobval = 1; } setdaytemp = setdaytemp + knobval; if (setdaytemp < 1) { setdaytemp = 1; } if (setdaytemp > maxday) { setdaytemp = maxday; } lcd.print (setdaytemp); lcd.print(" "); setday(); } int sethours () { lcd.setCursor (0, 0); lcd.print ("Set Hours"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { return sethourstemp; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { knobval = -1; } if (knobval > 1) { knobval = 1; } sethourstemp = sethourstemp + knobval; if (sethourstemp < 1) { sethourstemp = 1; } if (sethourstemp > 23) { sethourstemp = 23; } lcd.print (sethourstemp); lcd.print(" "); sethours(); } int setmins () { lcd.setCursor (0, 0); lcd.print ("Set Mins"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { return setminstemp; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { knobval = -1; } if (knobval > 1) { knobval = 1; } setminstemp = setminstemp + knobval; if (setminstemp < 0) { setminstemp = 0; } if (setminstemp > 59) { setminstemp = 59; } lcd.print (setminstemp); lcd.print(" "); setmins(); } int setmode () { //Sets the mode of the timer. Auto, On or Off lcd.setCursor (0, 0); lcd.print ("Set Mode"); pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { EEPROM.update (0, TimerMode); //write the mode setting to EEPROM return TimerMode; } lcd.setCursor (0, 1); knob.write(0); delay (50); knobval = knob.read(); if (knobval < -1) { knobval = -1; } if (knobval > 1) { knobval = 1; } TimerMode = TimerMode + knobval; if (TimerMode < 0) { TimerMode = 0; } if (TimerMode > 3) { TimerMode = 3; } if (TimerMode == 0) { lcd.print("Off "); lcd.print(" "); } if (TimerMode == 1) { lcd.print("On "); lcd.print(" "); } if (TimerMode == 2) { lcd.print("Auto "); lcd.print(" "); } if (TimerMode == 3) { lcd.print("Auto Extend"); lcd.print(" "); } setmode (); } int CalcSun () { //Calculates the Sunrise and Sunset times DateTime now = RTC.now(); sunTime[3] = now.day(); // Give Timelord the current date sunTime[4] = now.month(); sunTime[5] = now.year(); myLord.SunRise(sunTime); // Computes Sun Rise. Sunrise = sunTime[2] * 60 + sunTime[1]; // Sunrise returned in minutes past midnight SunriseHour = sunTime[2]; SunriseMin = sunTime [1]; sunTime[3] = now.day(); // Uses the Time library to give Timelord the current date sunTime[4] = now.month(); sunTime[5] = now.year(); myLord.SunSet(sunTime); // Computes Sun Set. Sunset = sunTime[2] * 60 + sunTime[1]; // Sunset returned in minutes past midnight SunsetHour = sunTime[2]; SunsetMin = sunTime [1]; } void ShortPush () { //This displays the calculated sunrise and sunset times when the knob is pushed for a short time. for (long Counter = 0; Counter < 604 ; Counter ++) { //returns to the main loop if it's been run 604 times //(don't ask me why I've set 604,it seemed like a good number) lcd.setCursor (0, 0); lcd.print ("Sunrise "); lcd.print (SunriseHour); lcd.print (":"); if (SunriseMin < 10) { lcd.print("0"); } lcd.print (SunriseMin); lcd.setCursor (0, 1); lcd.print ("Sunset "); lcd.print (SunsetHour); lcd.print (":"); if (SunsetMin < 10) { lcd.print("0"); } lcd.print (SunsetMin); //If the knob is pushed again, enter the mode set menu pushlength = pushlengthset; pushlength = getpushlength (); if (pushlength != pushlengthset) { lcd.clear (); TimerMode = setmode (); } } } void remoteClockSet () { typedef struct rxRemoteData //Defines the received data, this is the same as the TX struct { int TX_ID; int Hours; int Mins; int Secs; int Day; int Month; int Year; }; struct rxRemoteData receivedData; uint8_t rcvdSize = sizeof(receivedData); if (vw_get_message((uint8_t *)&receivedData, &rcvdSize)) { if (receivedData.TX_ID == 1) { //Only if the TX_ID=1 do we process the data, and set the DS1307 int TX_ID = receivedData.TX_ID; int Hours = receivedData.Hours; int Mins = receivedData.Mins; int Secs = receivedData.Secs; int Day = receivedData.Day; int Month = receivedData.Month; int Year = receivedData.Year; RTC.adjust(DateTime(Year, Month, Day, Hours, Mins, Secs)); //set the DS1307 RTC CalcSun (); //refresh the sunrise and sunset times lcd.clear(); lcd.setCursor (0, 0); lcd.print ("Clock Updated"); delay (1000); lcd.clear(); } } }

Radio Rentals Model 218 radio, repairs and restoration.

My good friend Derek, has once again dropped off a challenge.

"Always wanted a set with a magic eye. This one's got no mains lead. Can you sort it?"

Why not...

It's a well designed set, with long, medium, shortwave and FM bands. The FM band only covers 88-101 MHz, as the police used the upper bit to 108 MHz as late as the 1980's in the UK.

It's tone control isn't the conventional variable control, but a three position switch. I can't really see why this was done. It involves a rotary switch, and 3 caps and resistors, rather than a pot, and one cap. Strange... maybe a switch and caps were cheaper than a pot !?


This set is a "purchase model", rental sets were marked as "Property of Radio Rentals." It dates from about 1956/57

Nice un-cluttered chassis...


















First off to disconnect the mains smoothing cap and hook it up to the MK87 "Dreadnaught" capacitor reformer, and leave each section to reform.

It doesn't take long, the capacitor isn't original, and is in fine shape.

 Odd "dog bone" resistor (yellow body, purple end, red spot!) ... more the sort of thing you'd find in a 30's or 40's receiver forms part of the power supply filter... can't be original, can it?









A few caps are evicted as a matter of course, and the switches and pots are cleaned up.











Initial results on LW and MW are good, then... POP ... silence.... A new EABC80 valve restores audio. Faults are not going to be easy to find, as I have no service information on this set.
Shortwave works OK too, not much selectivity, but that's only to be expected really. FM is awful. Almost nothing.... it's unstable. A quick sweep with the signal generator shows the thing to massively high in frequency. It's tuning about 140-150 MHz! A long period of head scratching, and tracing signals with the 'scope shows there's a 68pF capacitor open circuit. That brings the tuning back into range. It's not very sensitive, but things improve with a re-alignment of the IF and front-end. One problem remains. It's not good at handling modern broadcasts. The deviation is too wide, and bass is horribly distorted. Not much I can do about that really.

I spoke to Derek, and he's not too fussed about the FM, so it's time to crack on... Derek would like a line-level audio in though, for MP3 use, which is easy on this set, as it's transformer isolated, and has a "gram" input we can use...

A 3.5mm jack is added to the gram input, and shunted with a 10K resistor to earth, and 20K in series. Works really well, but gives us an electrical safety issue, as if a fault were to develop, the chassic could become "live", as would the MP3 player! Thankfully as the chassis is isolated by a transformer, we can add a 3-core mains lead. Testing this out gives no issues :)

Sound quality from it's large Goodmans speaker and EL84 amplifier really are very good indeed.

Magic eye is a little dim, but works well.. The "wings" close up as the signal strength increases to show when the set is correctly tuned.

So to box it all up, and final test. MP3 input works well.... but nothing on the radio ! Back out with the chassis again. Poking about around the wavechange switch, and there's a wire broken! Duly soldered back on, and still nothing! Traced the signal back to the EACB80 again.... (?) Starting to doubt my sanity, when I find another broken wire on the valve base from the IF transformer! I wonder if that was the original problem with the valve, and changing it just caused the broken wire to meet up again? Yep, replacing the valve with the original and it's still good.

Soak test for a few hours, and it seems fine ..!

"Just a wire off" .... sheesh!


Cleaned up nicely too.

Citroën C1 (Mk 1), Peugeot 107, Toyota Aygo (Mk 1) (2005-2014) - Changing the dash illumination colour.

Many many moons ago I wrote an article on changing the colour of the dash illumination on the very excellent C1,107 and Aygo cars. It's got lost in the mists of time somewhat, so I'm going to re-create it here, by popular demand! I did this some 6 years ago, so please excuse the rather bad photography (like it's ever been great anyway!!)

Best I add a disclaimer, in addition to the usual one on the right.

Don't try this at home. I will not be held responsible, under any circumstances, if you damage your car. This requires accurate soldering to delicate and tiny components. 

Right, having got that out of the way....

We'll start with the binnacle lighting first...

So, open the bonnet and disconnect the NEGATIVE pole of the battery. Done that? Good....

Close the bonnet and arm yourself with a No.1 and No.2 Philips screwdriver, and a 10mm spanner or socket, a good quality soldering iron, some solder, desoldering braid, decent tweezers, 10 off PLCC-2 type SMD LED's and 50 off 1206 SMD LEDs in the colour of your choice.... oh and a sewing needle (yes, really) and a bit of connector block.

Turn the steering wheel to the right, to reveal one of the binnacle cover screws. Remove it.....













Turn the wheel to the left, and remove the other screw...

After a bit of jiggling, remove the cover....

... to expose 2 10mm bolts....












... and remove the two bolts ...















... gently easy the instrument binnacle forward to allow better access to the wiring, and remove the connectors, starting at the top. Each connector has a little catch. Once the catch is pressed, the connector should come out of it's socket easily...

Don't worry about noting where all the connectors came from, as each one is unique and will only fit in one socket.





Now take the binnacle off, and retire to the workshop/kitchen/dining room table!














Cleanliness is the key here, so go and wash you hands, and if you have any of those nitrile or similar gloves, don a pair now. You don't want to be leaving fingerprints on the inside of your speedo once we've got it apart....

Now, gently push in the two clear plastic catches, as shown here....











And there are two similar catches at the rear of the speedo to unlatch too.













Once these are released, you can lift off the clear cover.













Next wrap a piece of wire or string round the pointer, and gently pull it off.













Now release the black plastic catches holding the surround in place, two shown here, and one on each side...













... and gently un-clip the surround....














.. remove the speedo face...














... and lift out the diffuser...















... remove the four philips screws holding the speedo electronics to the brown back & sockets.... one is a different length. Make note of which one it is!











Remove the speedo electronics from the brown back assembly. This will take some gentle prying to get the socket to release.












And place the back safely out of the way....













Now comes the tricky bit. First off, make yourself a DIY hole clearing tool, with a needle mounted in a piece of connector block..












Get yourself some good quality desoldering braid. Don't be tempted to use one of those nasty spring-loaded pump type desoldering tools. They have an unpleasant habit of removing the solder, along with the tracks on the board, which will be difficult and time consuming to repair. I personally rate Chemtronics braid. It's good stuff....

Now, desolder the 21 pins connecting the odometer and fuel gauge LCD to the board. Take your time. Breaking this would not be good news. Once they are all desoldered, check each pin can wiggle a bit in the hole with the needle, and lift off the while plastic front, along with the LCD. Clean up the holes, by warming the DIY hole clearing tool with the iron, and inserting it into the holes, pushing out any remaining solder. Clean up with the braid, and breathe a sigh of relief.




Now we come to change the LED's themselves.

PLCC-2 LEDs have a small cut out in one corner. This marks the cathode. There is a small arrow printed next to each LED and the cut-out must be at the pointed end of the arrow, as shown in the picture...







Using the desoldering braid, desolder the LEDs ringed in the picture. LEDs ringed in red are the backlight LEDS, and the LED ringed in blue is the illumination for the pointer. You can make them different colours if you wish...

Heating the LEDs for too long with the soldering iron will destroy them, which isn't much of an issue when removing the old orange ones, but you want to be careful when soldering the new ones in place.

Once this is done, carefully reunite the LCD display, still on the white surround with the electronics are resolder it in place. Replace the electronics back into the rear cover, making sure the socket seats home, and replace the 4 philips screws, ensuring the long one goes back in the right hole. Replace the diffuser, and fit the face. When pushing the pointer back on, fit it pointing towards 110 MPH, and once seated move it round to 0.
Replace the black cover and the clear cover. Done.

Ignore this bit if you haven't got a tachometer (rev counter).....

Squeeze the tacho slightly, and grip the front surround. It should pop off easily.

Remove the philips screw in the rear of the tacho, allowing it to be pulled out slightly.













Unclip the black plastic surround and remove the surround and plastic lens in one piece...

Remove the pointer with a piece of wire or string in the same manner as we removed the speedo pointer.

Undo the two screws securing the face to the speedo...






Remove the electronics and face in one piece, disconnect the plug, and remove the two screws.













Replace the two LEDs shown, remembering the arrows...











and reassemble.

Take the binnacle back out to the car and re-fit it.

Good eh??

But we're not done yet!









Radio looks awful in orange now doesn't it? ... and that heater illumination ... ugh! ... and the headlight aim switch ... horrendous!

Let's deal with the radio and heater.










Set the heater fan to the II position, and locate the small gap in the knob underneath. Gently prise it off, using a piece of cardboard to cushion the dash so we don't scratch it.

Remove the screw.









Get a credit card or something (I've got strong finger nails!) behind the cowling, and pull it off. It shouldn't put up much of a fight.












4) Remove the pulgs and sockets from the radio (one white, on black (have little release levers on one side) and the aerial plug (just pulls off)) , and the heated rear window switch, hazard warning switch and (if you're lucky) the air con switch (have release buttons on the top or bottom).








These are green white and black respectively. Cart the whole assembly inside to the operating theatre.

Remove the radio from the dash. Two sprags holding the radio in each side. Two on the top and two on the bottom.












This requires use of 14 fingers, or some choice expletives, or both.

Put the cowel to one side, and remove the front from the radio. Two small philips screws each side, and one clip each side, two on the top and bottom.












12 fingers only required this time, also fewer expletives.












Remove 8 screws from the display PCB and remove. It will unplug from the push button sub-panel, leaving that in place.













Remove 4 screws from sub panel and remove.












Right. Here are the LEDs we're going to change. They are 1206 SMD LEDs, you'll need 50 of them (you'll have a few left over)





























1206 LEDs are tiny!










There are 17 on the sub panel and 27 on the display PCB. I know I told you to get 50 , but you will lose some ;) And anyway , it's a minimum order quantity :D

Remove a new diode from it's packaging to examine it. Marked on it somewhere is it's polarity. The mark will indicate the cathode. In the case of my diodes, there was a green mark on the underside. This pointed to the cathode.








The cathode of the diode on the PCB is marked with a continuous line around the end of the diode. In the case of the picture below, it's to the right. All of the diodes we are changing have there cathode to the right, or to the top if they are vertically orientated.









Desolder the first diode (I actually desoldered the whole lot, it saves time, but if you're new to this, take your time). Use the solder wick to suck off the solder, then you should find a slight push with the iron tip, will remove the diode from it's lands. Use a nice fat tip for this job. Clean up with solder wick. Add a touch of fresh solder onto each land. The PCB's in this radio are really well made and will tolerate quite some abuse before the print becomes damaged.





Grab your new diode in some tweezers, making sure you know which end is the cathode. Line the new diode up to it's solder lands, and just melt the solder with the small iron, so as to solder the one end of the diode in place. Remove the tweezers and melt the solder on the other end.





Repeat for the other 16 diodes on this board.


Put the board to one side , it's time to tackle the display board .... "What's so tricky And?" I hear you say .. it looks similar to the other PCB .. unfortunately there are 12 diodes UNDER the LCD crystal display, so it's got to come out.

Twist the 4 tags holding the display screening can to the board, and desolder the two points.













Desolder the two multipin connectors to the display, just underneath the CD slot. TAKE YOUR TIME. The display crystal is very fragile. One crack, and it's game over. I chose to flood the connectors with solder and run the iron up and down the whole length until every joint was wet, the display will then gently come out. Solder wick is another option. Once the display is out , put it somewhere safe.

Using the hole clearing tool (OK , it's a pin and a bit of connector block) and the solder braid, clean up the connectors.

Change the diodes in the same manner as you did on the first board.

CAREFULLY re-fit the display. Don't forget to twist the tags and solder the can.







If you have a bench supply, plug the boards in and power up to check it all lights up nicely. You'll need to connect +12 Permanent, and +12 lights.

Damn, that looks good....








Right. That AUX socket on the front... what a pain. Lead from your phone dangling all over the place looking untidy... Fancy moving it somewhere sensible? Read on.....

Move back to the sub-board, and looking at the aux connector, cut the track as shown...

It's uncut here...











...and after the incision is made. This is to fool the electronics into thinking there is a plug in the socket.

Turn the PCB over, and connect a piece of twin and screen cable to the points as shown.












Right channel is red, left black and the screen is ground.



Replace the sub-panel, and the main display PCB, and carefully route your new cable out of the front... it's tight , but mine fitted.

Refit the radio in the dash, again routing the new cable. I chose to route mine to the rear of the clutter box...  You'll need to solder a 3.5mm stereo jack to the end, tip is left, ring is right, and sleeve is ground.

OK... it's going well... now the heater... You can buy replacement LED lamps for the bulbs in there now. I chose to use a couple of ordinary 5mm blue LEDs, and solder them in.. It's easier if you get the right LED bulbs.

I cut the tops of the LEDs in an attempt to diffuse the light a bit, otherwise you'll end up with two spots. Not a good look. Note the 780 ohm resistors.

Undo the panel mounting screws...













 ...both of them...

...and hinge the panel forward. You will see the old bulbs in there holders, just pull 'em out, and fit the new ones or solder in your LEDs. If they don't light, you may have them in the wrong way round. If the light is still focussing as two spots, just bend the LEDs so they face away from the front. This is easier if you have soldered separate LEDs, as I did. Once it's nice and even, screw the panel back in place, and refit the radio... Give it a try.... Nice....





... except for the headlamp aim switch ... still orange... nope, it'll have to go....




Remove the philips screw holding the outer dash on....













Pull the dash down, and pop the switch out, un-plug it and back to the operating theatre....

Pull off the cover.....

Cut off the orange LED.













... and solder in a PLCC-2 diode in it's place, with the cut-off corner facing the outside edge.

Push the cover back on, and refit the switch and dash.....








There. It's done. In all it's blueness....

... or pink if you prefer ;)












Thanks to Hanna for the pink pic. White looks good too!