Vidor Gem.

[pepmin 1]

Hi. What would be the best equivalent value for a 6 uf electrolytic capacitor ? Thanks Colin.

[ms660]

4.7uF.

Lawrence.

[pepmin 1]

Thanks Lawrence.

[pepmin 1]

The radio has started to whistle and chirp quite badly now so I took all off the electrolytics out off circuit today.I soldered new ones back in bad this made no difference to MW. It has however made LW worse. LW was fine before I did this but now it just pulses in and out? I have checked and rechecked my connections. I was asked to do a voltage check on the radio and also did this today. The voltage before switching on was 5.588 and after switch on 5.536. Apart from pulling out all of the non electrolytics would anyone have any other ideas. Thanks Colin.

[crackle]

Have you done all the voltage checks around each transistor yet, I note down voltage on each E, B C connection for each transistor, and compare to the details given on the service manual.
This can help show up a faulty capacitor which is leaking badly.
Mike

[pepmin 1]

Hi Mike, No I havent done this yet as the readings wouldnt tell me very much. I could offer them up here though if they are different to the service data and maybe someone could have a look at them for me. I will have a go tomorrow.The data says to do this with the gang set to maximum capacitance ? Which way would that be ?

[julie_m]

The capacitance depends on the area of overlap between the fixed and moving plates, so maximum capacitance will be when the gangs are fully meshed -- a larger capacitance takes longer to charge and discharge, so this will also be the low frequency / long wavelength end of the dial, and minimum when they are barely overlapping -- the high frequency / short wavelength end. If there is a strong station there, though, you might want to tune it away from that a little, lest the presence of a signal affect the readings.

[pepmin 1]

Thanks Julie. I am not having much success with taking transistor readings. On MW there is a continual loud clicking noise and this maybe upsetting my readings ? The readings are not stable and increasing and decreasing with the clicking I think ? For example I can get a reading off 5.850 then it shoots up to 980 down to 535 then back up again. This happening on all transistors. On LW there is no clicking but following the data it says to do this checks on MW. I am using a digital multi meter and I can see auto range on it as I am doing these checks. Will this have a bearing on the readings ? Colin

[pepmin 1]

Okay my little brain is hurting now. I have taken C10 out off circuit again and replaced it with a new one. It still clicks and whistles. I have removed that capacitor and the radio is working fine with no C10 capacitor in circuit . All whistling and clicking has gone. I have lost a bit off volume but the radio is still clear and loudish!! I may attempt to take voltage readings again later on. But for now the sun is shinning and I have spent far too much time on this radio. I wish I never bought the flipping thing.

[pepmin 1]

I have finally resolved the issue with the radio. I had exhausted the capacitor route and was resigned given my skill level to not being able to repair it. It was bugging me though so I gave it another go. In my mind the problem centred around the C10 area off the circuit so I had another look at the service data. Bear in mind that schematics are just a bunch off squiggly lines to me but I concentrated around C10 and came up with the idea that the R7 510 ohm resistor may have gone high or low ( yes shooting in the dark ), It didnt look that good and sure enough when I removed it the end of it fell apart. I soldered a new one in its place connected C10 back into the circuit and all off the whistling and chirping etc came back again. I had been thinking about the TR2 Ediswan XA101 transistor for a while but kept on dismissing the idea as I didn't know if this could even cause the problems that I was having. I had a look on line to see if I could find an equivalent as I knew finding an original would not be easy. The transistor I came up with was a OC45 and the only one i could find was on an old bush radio that I had. I removed the XA101 and put the OC45 in its place. All off my problems were gone. No whistling or chirping and bags off volume and the tone is better as well. Just to make sure I put the original transistor back in place again and all off the problems were there again. All off the original capacitors have been reinstated again just because I want as many off the original components back on the radio, and I think I proved to myself that there were still okay. The radio has been playing away for a couple off hours now and so far everything is fine. Colin