Samsung 3 band radio cassette, model: STF55L

[Formby Mal]

Hello, I wonder if any one can help. I have my parents vintage Samsung 3 band radio/cassette: model ST F55L, the sound is brilliant and I would like to use it in my shed but it needs an FM receiver, so my local radio repairman says - he can't get the part. Does anyone know where I could try and get the part or anyone who could repair it for me? Thank you very much for your help, it seems such a shame to bin it. Regards, Mal.

[paulsherwin]

Sorry Mal, that doesn't make much sense.

Are you saying the radio cassette works on LW and MW, but not on FM? If so, the most likely cause is dirt on the wavechange switch contacts. Far Eastern designs of that era are usually very reliable electronically.

Are you looking for a professional to repair it for you? If so, you can start a thread here: https://www.vintage-radio.net/forum/...play.php?f=145

[Formby Mal]

Hi Paul, thanks for your reply. I'll have look at what you said about dirt on the wavechange switch contacts, but the chap that had a look for me seemed to think it was the 'FM receiver' that needs repalcing. He works on 'old' equipment and was adamant that he could not get the part or it wasn't worth replacing. Yes the LW and MW work fine just the FM not working. Regards, Malcolm.

[Station X]

All very vague. What part are we talking about? Most parts tend to be generic rather than model specific.

Are the make and model correct? Nothing comes up on Google.

[davidw]

Is it one like this attached photo
Switch contacts would be my first place to look.

[Formby Mal]

Hello and thanks for your replies... Graham, yes that is the right model as Dave found the correct one (see photo). Well it seems, from what this local repair bloke says, it needs, as he said, "an FM receiver" probably a 'chip' ?. But I will have a look at the fm switch and see if that is the problem. I remember looking there before and could not get into the mechanism but will have another look. Thanks once again guys, much appreciated. regards, Malcolm.

[Herald1360]

Is it possible to ask your repairman to give you the proper technical description of the actual part(s) he believes to be faulty? The "FM Receiver" is meaningless unless the set has a separate dedicated module for the FM "front end" part of its circuits. Even then, it's unlikely that the only possible fix would be a complete new module.

It is unfortunately entirely possible that the time cost of a commercial repair would be uneconomic compared with the set's likely market value.

[mark2collection]

Hi Malcolm,

Having worked on some radio/cassette players over the years, and considering some of the harsh conditions they are either stored in, or used in, they still soldier on. It's highly unlikely a complete module will need changing.

As others have said, grubby switch contacts is a possible, may be worth 'exercising' them all (set off to begin with) and see if FM springs back to life.

It's also worth checking any multiplugs inside, since any oxidisation on these can cause issues, and one last oddity, does the set have a 'Stereo' indicator or beacon?

This generation of radio would almost certainly use an LED (these last years) but some do use a filament lamp.

The last Akai I saw (2 years ago, had been stored in a loft for 25 years previous) had no FM. Switches & multiplugs operated & looked ok but were cleaned all the same, the connector to the front-mounted LED 'Stereo' indicator however, had one leg corroded. Once nice & shiny FM was restored. Some sets with failed stereo indicators will only work in mono, others (it seems) give no sound what so ever.

It really wouldn't take too much to make her sing again, and quite often the electronics in these live on one whole PCB, though some don't.

Best regards,

Mark

[Formby Mal]

Thanks Chris and Mark, I have had a look at the FM switch and turned it on and off quite a few times but with no result, it is about 3 inchs long and about 1/2 inch square. I'll have a go at asking the 'repair man' what he was on about - he did seem to be a bit vague. As regards the 'stereo' questiion yes it is a stereo model with what looks like an LED light. the photo that Dave put on is the correct model. I will have a look for the multipluigs and take a photo of the inside to see of that will help. Once again 'Guys' thank you 'all' very much for your help. Regards, Malcolm

[paulsherwin]

It's possible that the repairman identified a dead chip in the FM front end - this is unlikely, but not impossible. A replacement will indeed be hard to find, and fitting it is a fairly skilled job. If this is the case, then this player is likely to be beyond economic repair unless it has very great sentimental value for you.

See what he says. If he emails you with info, paste it into this thread. Some members here have extensive experience with this sort of electronics, and will be able to advise you further.

[Formby Mal]

Thanks Paul and everyone else. I spoke with that repair man and he said it was the 'FM tuner module'. I will have a look at the multiplug situation tomorrow. Thanks once aagin everyone. Regards, Malcolm.

[G6ONEDave]

According to the service manual this set has the following chips; AN7213 or KA3213 (FM RF amp and osc mixer), HA12413 or BA4220 (FM/AM IF amp and detector), AN7420 or KA2263 (FM mpx). These chips are all on the main pcb and not a seperate pcb just for FM only. I could scan a copy of the Samsung ST-F55L manual if it would help.

Dave

[paulsherwin]

The KA3213 does seem to be a fairly widely used Samsung chip of the right era, but getting hold of one won't be easy.

[Formby Mal]

Hi Dave (G6ONE), The scan of the ST-F55L manual might come in useful in the future if it needs a chip. Thank you very much. Regards, Malcolm

[G6ONEDave]

PM sent.

[Formby Mal]

Hi Guys, I think I have uploaded 2 photos of the PCB board. I couldn't find the multiplug units or even the 'FM tuner module'. Thanks for all your help. cheers, Malcolm

[Formby Mal]

Hi Guys, Dave (G6ONE) very kindly sent me the manual for this ST F55 Samsung radio and in his earlier post he, and Paul Sherwin, mentioned some 'chips' :- AN7213 - ICFM front end / AN7420 - ICFM MPX PLL and HA12413 IC AM FMIF, but I can't find them on the exploded plan (see attached). Dave also mentioned if I had a multimeter that I could measure the DC volts around those 'chips' and post on this site. I haven't got a multimeter but was going to ask some friends, but don't know where to look on the board anyway. So any ideas? Thank you all so very much for trying to help me. Cheers... Malcolm

[G6ONEDave]

Mal the chips in question are IC1 located top left in the PCB layout page 10, IC201 located bottom left and IC251 to the right of IC201. IC1 is a 7 pin single in-line package, IC201 is a 16 pin dual in line (8 pins each side or if you prefer 2 parallel rows of 8 pins) and IC251 ia a 9 pin single in-line package.

Dave

[paulsherwin]

The KA3213/AN7213 (IC1) can be seen on the extreme left of the circuit board in the first photo in #16, below the ferrite rod and left of the tuning capacitor.

It wouldn't be a good idea to start changing chips without doing some further investigation though, even if you can find a supplier.

[Formby Mal]

Thank you both - Dave and Paul, I will have a look and try and get a multimeter, just thought would they be soldered on from the otherside or just push in? Thank you so much. Cheers, Malcolm.