29-10-2011, 06:34 PM
There are still bargains to be had in this world, if you look and listen. A Truvox for 30p. Well, you cant be bitten can you? Er.... well...
This machine was going cheap for a reason, and the reason was that somebody had been there before me and made a bit, well, a lot of a mess. The Motor didn't turn and the other person had tried to re-design the power supply to only use one bridge rectifier as the other had stopped in it's tracks, as it were.
So, out of the cabinet it came and my first port of call was the motor. The previous restorer had tried to tie the mains lead somewhere stupid and it was jamming the motor. Precisely what he wanted to achieve by putting the mains lead here I don't know, but I withdrew it and mounted it somewhere more sensible.
With the power supply reconnected, I tried the motor and it now span round merrily. Nothing else did until I pressed one of the buttons on the left. Play seemed OK on all three speeds, wind was OK but nothing on rewind until I nudged the wheel towards the deck, when it started to work.
Clean the deck time! The Power Supply could wait, as I wanted the deck to operate properly first. The keys were loosened and cleaning and a little oil were introduced in a few places. The keys now felt good and they operated with a nice, positive action. The wind problem was no better however, so I took the wheel off inside and roughened the edges. This being off, it revealed how it operates on Fast Forward and Rewind. So I took the next bit off as well (Circip, washer and spring) and carefully cleaned the three other areas underneath. Then I put the whole thing back together and made sure that the hole underneath met up with it all and circlipped the lot back in place.
Note for the wise : make sure this lot marries up OK before putting the circlip on otherwise it'll do nothing and you have to start again.
The winds now worked when power and tape were offered up. So did the play, so now we turned our attention to the power supply. There were no really hard voltages here as the electronics are transistorised, but the person who had tried to mend this deck had, for some reason tried to make the PSU use only one bridge rectifier rather than two. A little bit of a mess had ensued and were the electronics positive ground? A circuit was needed and there was no trader sheet for it and my Hellyer book of tape recorders didn't cover it. So I had to ask, as I didn't want to risk wiring it up wrong and blowing up the electronics.
I soon found out that the unit was positive ground and one very helpful person sent me the diagrams while the rest made interesting comments about the deck and electronics. Yes, so it wasn't Truvox's best moment, but we need to preserve it for that reason alone.
There are two different power supply arrangements for this machine, both have two rectifier units but one has three large capacitors, one has two. The one that this unit had used 3 capacitors and of course 2 rectifiers. One of these had stopped working, so some personage had decided to try and work it all off one rectifier instead. I didn't look at how they had tried to do this, but stripped it out and started from scratch. There are three secondary windings on the mains transformer, one low voltage for the pretty light, one AC 100v line and one AC 200v line. The two bridges were tied on the positive pins and the negative lines were different.
I rebuilt the power supply as per the diagram and then tried it again. There was a bump from the speaker at switch on and a finger to the back of the heads made a noise in the speaker. On went a test tape and we had music in the kit--- sorry workshop. As this tape is also the one I test record on, I switched it to record and finally remembered the numbers from one to ten. These were played back on both channels so we didn't have any other problems. I say this because, as I have found out, this machine was in no way Truvox's finest hour and some were modified electronically around the bias stages.
Now a tape recorder apart and a tape recorder together can be two different machines. Do make sure that the speaker connections are secure before you try to reassemble it! After taking it out of the case, making the speaker contacts again and putting it all back together, it seemed to work again!
I put one of my classical music tapes on and Ludwig Van's 9th came out of the speaker, and I viddied such beautiful things, oh my droogs. Then my Devotcha, Dilys came in.
'Your Droogan Leader would like a cup of tea', Steve told her.
'Not Moloko?', she replied.
'Tea', I replied. 'I'm past all that now.'
This machine was going cheap for a reason, and the reason was that somebody had been there before me and made a bit, well, a lot of a mess. The Motor didn't turn and the other person had tried to re-design the power supply to only use one bridge rectifier as the other had stopped in it's tracks, as it were.
So, out of the cabinet it came and my first port of call was the motor. The previous restorer had tried to tie the mains lead somewhere stupid and it was jamming the motor. Precisely what he wanted to achieve by putting the mains lead here I don't know, but I withdrew it and mounted it somewhere more sensible.
With the power supply reconnected, I tried the motor and it now span round merrily. Nothing else did until I pressed one of the buttons on the left. Play seemed OK on all three speeds, wind was OK but nothing on rewind until I nudged the wheel towards the deck, when it started to work.
Clean the deck time! The Power Supply could wait, as I wanted the deck to operate properly first. The keys were loosened and cleaning and a little oil were introduced in a few places. The keys now felt good and they operated with a nice, positive action. The wind problem was no better however, so I took the wheel off inside and roughened the edges. This being off, it revealed how it operates on Fast Forward and Rewind. So I took the next bit off as well (Circip, washer and spring) and carefully cleaned the three other areas underneath. Then I put the whole thing back together and made sure that the hole underneath met up with it all and circlipped the lot back in place.
Note for the wise : make sure this lot marries up OK before putting the circlip on otherwise it'll do nothing and you have to start again.
The winds now worked when power and tape were offered up. So did the play, so now we turned our attention to the power supply. There were no really hard voltages here as the electronics are transistorised, but the person who had tried to mend this deck had, for some reason tried to make the PSU use only one bridge rectifier rather than two. A little bit of a mess had ensued and were the electronics positive ground? A circuit was needed and there was no trader sheet for it and my Hellyer book of tape recorders didn't cover it. So I had to ask, as I didn't want to risk wiring it up wrong and blowing up the electronics.
I soon found out that the unit was positive ground and one very helpful person sent me the diagrams while the rest made interesting comments about the deck and electronics. Yes, so it wasn't Truvox's best moment, but we need to preserve it for that reason alone.
There are two different power supply arrangements for this machine, both have two rectifier units but one has three large capacitors, one has two. The one that this unit had used 3 capacitors and of course 2 rectifiers. One of these had stopped working, so some personage had decided to try and work it all off one rectifier instead. I didn't look at how they had tried to do this, but stripped it out and started from scratch. There are three secondary windings on the mains transformer, one low voltage for the pretty light, one AC 100v line and one AC 200v line. The two bridges were tied on the positive pins and the negative lines were different.
I rebuilt the power supply as per the diagram and then tried it again. There was a bump from the speaker at switch on and a finger to the back of the heads made a noise in the speaker. On went a test tape and we had music in the kit--- sorry workshop. As this tape is also the one I test record on, I switched it to record and finally remembered the numbers from one to ten. These were played back on both channels so we didn't have any other problems. I say this because, as I have found out, this machine was in no way Truvox's finest hour and some were modified electronically around the bias stages.
Now a tape recorder apart and a tape recorder together can be two different machines. Do make sure that the speaker connections are secure before you try to reassemble it! After taking it out of the case, making the speaker contacts again and putting it all back together, it seemed to work again!
I put one of my classical music tapes on and Ludwig Van's 9th came out of the speaker, and I viddied such beautiful things, oh my droogs. Then my Devotcha, Dilys came in.
'Your Droogan Leader would like a cup of tea', Steve told her.
'Not Moloko?', she replied.
'Tea', I replied. 'I'm past all that now.'
If we've always had that, why is the car boot open? You aren't smuggling in another old TV are you...?
