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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 26th Mar 2023, 11:11 pm   #1
Join Date: Feb 2023
Location: Watford, Hertfordshire, UK.
Posts: 86
Default Tandberg TCD310 overhaul.

The Lockfit transistors used in these can cause all types of weird problems. They are BC147 npn lots of and about four BC157 pnp. Use BC549C npn and BC559C pnp as equivalent replacements. I just change them, they are known to fail especially in equipment that is approaching 60 years old. Expect to pay about £6 for fifty transistors. I also change all the electrolytics. The Tantalums seem reliable though, I have come across very few failed Tantalums in these TCDs. Sometimes the carbon track on the presets can cause problems, I change these as well if they are causing problems. All the multi plugs and sockets will have tarnished connections. I clean the socket pins with a fibre brush. The plug pins I remove individually and re-tension, I spray some switch cleaner into the plugs and re-fit. The worst offender are the plugs and sockets on the small panel where the head wires plug into, here I dispense with the plugs and sockets and hard wire. Without extension leads it is nearly impossible to fault find on the TCD310 with the boards in situ. The underneath of the main board is accessible though. I have never had a problem with the Dolby boards which are also accessible, you can check here the signal going in and coming out.
Mechanically. There are lots of adjustments to adjust to have the tape follow the correct path. It is best to leave these alone, hopefully they haven't been messed with. If they have then there is a tedious procedure to adjust to correct this. You will need specialist tools.
The old grease which acts like glue under the slide should be thoroughly cleaned off and re-greased. Be careful not to loose the three ball bearings. The spring here should be on the first notch. The two pinch wheels shoud be checked for wear. Non original replacements are available, there is a Chinese one that is fine or better still "Fix Your Audio" have one that is perfect. After replacement you will need to adjust so as both pinch wheels come into contact with the capstan shafts at the same moment. The capstan sintered bushes would benefit from a drop of oil, also the top bush on the capstan motor, the capstan motor bottom bush which is difficult to access luckily is designed so as not to dry out. There is (from memory) a felt pad here which is soaked in oil during manufacture, in the couple of capstan motors I dismantled before I realised it wasn't neccessary, this bush was soaked in lubricant. Also a drop of oil on the top bush of the reel motors is beneficial. I have never come across a capstan motor failure and only ever one reel motor failure.
I would guess that about 50% of the TCD310s that have passed through my hands had a worn or pitted play/record head. I have replaced these worn heads with Chinese ones that I had in my drawers without modifying the record equalisation circuit. I have never encounted a worn out erase head.
Finding a capstan belt that can better the published figures for the wow and flutter of this model is not easy. I spent a lot of time trying to at least fit a belt that equalled these specifications. A lot of the belts I bought from various different suppliers were a lot worse than specification. The wow and flutter was audible, this was probably acceptable at the time of manufacture, but not now. I can remember lusting over a Tandberg TCD310 when they first came out, they cost twice as much as the Sony deck I settled for. The wow and flutter of cassette decks of the time was one of the reason that HiFi enthusiasts rightfully in my opinion regarded cassette decks as low fi. It was only about thirty years after this that I realised that the cassette medium could and does produce excellent sound. I had in for repair / check over several Nak Dragons that one of my then customers was buying to sell on. These Naks changed my perspective to the fact that cassette decks can and do produce quality sound. I digressed back to the TCD310, eventually I did find a capstan belt that not only equalled specification but was better than the published figures.
These TCD 310s are well worth going to the trouble of repairing and overhauling, although they can be a real pig after nearly sixty years if not attended to with care.

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Old 27th Mar 2023, 12:22 am   #2
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Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,264
Default Re: Tandberg TCD310 overhaul.

I had one about 20 years ago, and gave it to a mate( at the time) to repair and havenít seen it, or him since.
Last I heard he was teaching English in China.
"Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."
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Old 27th Mar 2023, 12:35 am   #3
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Join Date: Jul 2011
Location: Staffordshire Moorlands, UK.
Posts: 1,363
Default Re: Tandberg TCD310 overhaul.


Thanks for starting this thread and for the very useful info that you have just given us in the first post.

I have one of these excellent cassette decks which I bought at a bargain (serious bargain) price a few years ago in my 'to do' pile. I had always wanted one but back in the day they were way above what I could afford so when one in nice condition came up I couldn't resist. They are truly lovely machines and although mine works pretty well it isn't getting much use at the moment but there's sort of chaos in our house till some building work is finished and when it is the 'to do' list will be receiving the attention it deserves. When that time comes I shall be referring to your comments and perhaps I could message you with any questions that arise?

One thing that I did wonder about my deck is I think (although I might be mis remembering - it's been a while) I can detect a very small amount of play in the capstan bearings - should there be any detectable play? I'm guessing not and if that's the case do you know of a source for replacement oilite bushes? Perhaps the play will disappear with proper oiling... what type of oil do you recommend?

Thanks again,
Those who lack imagination cannot imagine what is lacking...

Last edited by fetteler; 27th Mar 2023 at 12:41 am.
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Old 27th Mar 2023, 10:28 am   #4
Join Date: Feb 2023
Location: Watford, Hertfordshire, UK.
Posts: 86
Default Re: Tandberg TCD310 overhaul.


I was using PDP65 for the bushes. I had a small bottle, which has disappeared. It more than likely fell off the bench and fell down that hole to the centre of the Earth, never to be seen again. All my searching has been in vain.
I might well be wrong with this, but I believe the original oil used was 100% synthetic. A small (tiny) amount of play usually in the top bush might hopefully be insignificant.
The best belts I have found are from ASWO. You require an account to order from them. They took over Chas Hyde accounts and all I had to do was give them my CHS details to obtain an account. They are a good source for many components including belts.
Steve there is no problem with messaging me. It is strange hearing from you today. Last week my Weller 24 volt iron kept going cold. I will sort this it is something to do with the magnastat. However the strange part is that I purchased the 24 volt transformer for this iron from you many years ago.

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