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I pulled the 2 most likely suspects, C25 and C26 out of the board and both measured high. C25 measured 1.418uf instead of 1uf and C26 44.14uf instead of 33.00uf. Both were replaced and I am happy to report that the tuner retains the correct frequency after power up now. Also checked R81 and...

Thanks for the information, all the out of specs electrolytics will eventually be replaced but due to my zero knowledge on rf circuits, I am taking baby steps and only replacing the suspected components followed by further testing of the unit for now. Going forward I will replace the caps in...

Thanks for sharing your knowledge so generously, it's currently work in progress, I have already replaced C26 and C25. Both of them measured high. Similar to your suggestion, I have replaced C25 which is1uf with film. Once the tuner is tested working after replacing C26 and C25, the rest of the...

Thanks for describing the operation of the circuit. The parts are on order. I will pull out the suspects to test and replace if necessary and will report back next week.

I gave D01 a shot of freeze spray for approximately 3 seconds and this is what pin32 of MSM5540 responded with : Thanks

Sorry, I just realized I have caused some confusion. I used freeze spray for the above test as well when you explicitly mentioned compressed air can. I repeated the tests with a duster: Initial Voltage 7.67 v After Spraying 7.69 v Quartz Lock Led Stayed On Stereo Led Stayed On Frequency on FM...

This is how the waveform looks at 20mS/div. I did not notice any significant change in amplitude / pulse width nor a bunch of pulses when air from a duster is directed at D01. Thanks for the help, I am learning a lot about radio from these postings.

Fortunately the MSM5540 seems to be kicking and alive. I blasted D01 with freeze spray, a little longer this time and I can observe a DC voltage swing as D01 approaches room temperature. Another observation is there's an obvious voltage change on pin 32 during power up: However I have...

Yes the voltage change and it went off lock. These are the results of the test and my observations: Initial Voltage 6.59 v After Spraying 6.13 v (took quite a while to settle to this voltage) Quartz Lock Led went from On to Off Stereo Led went from On to Off Frequency on FM Dial jumped from...

Thanks for the response.Yes the locked light go out when I touch the tuning knob very slightly.

Thanks for your encouragement. My eureka moment was short lived. After leaving it off overnight, it jumped to 90.7Mhz from 90.5Mhz on first power up in the morning. I still need a favor from you to have a quick look at the schematic at your convenience. Thanks

Thanks to Dr. Audio for helping thus far. The frequency stays rock solid now even after repeated power cycles. On further investigation, I have found that one jumper on board F3000 was wrongly configured. I don't think anyone has gone into this tuner and this is the original configuration from...

To eliminate the possibility of tuning into adjacent stations, I choose a station frequency of 91.30Mhz. The next station to the left is 90.5Mhz and to the right is 92.00Mhz. These are the measurements Tuning Left towards 90.5Mhz 91.30Mhz 7.34v (station frequency) 91.20Mhz 7.18v 91.10Mhz 7.28v...

Yes the voltage changes when the tuning knob is turned in both directions. Here are some recorded voltages. 90.4 Mhz 7.39v 90.5 Mhz 7.42v 90.6 Mhz 7.04v 90.5 Mhz is the station frequency.

I performed the adjustments. Although the digital frequency readout matches closely with the analogue dial after the adjustments, I still get a drift of +/- 0.1 Mhz during power up.

Noted with thanks. I will do the necessary adjustments and report back in a couple of days.

Yes the display read the correct frequency when it is in lock. I have a can of freeze spray, no problem with that.

Thank for the reply. Yes the lock light goes out when it drifts and comes back on when I retune it. One thing I forgot to mention is that I have very carefully cleaned the tuning capacitor and applied a very small amount of Deoxit Faderlube where the spring clips contacts the tuning shaft. Thanks

Thank for the reply. Yes the lock light goes out when it drifts and comes back on when I retune it. One thing I forgot to mention is that I have very carefully cleaned the tuning capacitor and applied a very small amount of Deoxit Faderlube where the spring clips contacts the tuning shaft. Thanks

I was given a Sansui T-80 in excellent condition. Tuner pulls in FM channel well and quartz lock is working. Only problem with this tuner is the frequency drifts by 0.1 to 0.2 Mhz after a power cycle. 90.5 Mhz could drift to 90.4 Mhz or 90.6 Mhz upon power up which necessitate re-tuning to 90.5...

Faceplate Removal Yes you need to remove the front panel to gain access to the dial pointer light bulb. Once the front panel is removed, you can replace the lamp from the top. I'd snipped off the wire as close to the faulty bulb as possible, leaving a good lenght of the original wire and...

Would this be a candidate after some modification ? Just came across this while searching for a cheaper option. I am not sure if it is the correct dimensions. This runs on 12 volts but I am quite sure it can be used after some mods. It's $1,70 a piece including shipping. 6500k as opposed to...

Not yet , but I intend to replace the signal path caps on the tone board with audio caps. But I have to learn to differentiate what is signal path and non signal path first.

Yes I faced the same problem when I recapped the tone board of my 2265B . The highs sounded metallic and piercing. I used Panasonic FC and FE for the recap of the tone board. Everything went well until the caps on the tone board were replaced. It was a complete disaster :tears: Kinda...

Through the recommendation of Aker's, I am currently recapping my 2265B exclusively with Panasonic FC and FM. Except the power amp board, all the other board has been recapped and I can already hear more open highs, very subtle though but definitely some improvement over the old capacitors...