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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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10th Nov 2022, 10:51 pm | #1 |
Triode
Join Date: Dec 2021
Location: London, UK - Galicia, Spain
Posts: 30
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JVC KD-D55 cassette deck brought back to use
Hello all,
Whilst clearing out my loft recently, I came across my old JVC KD-D55 cassette deck. I have some tapes that I want to transfer to CD/computer before the oxide on them deteriorates along with the audio. I purchased the three head design in the mid/early eighties. It has Dolby C, which I found to be better than ANRS/Dolby B as the higher treble frequencies were not attenuated as much, and music sounded ‘clearer’ and it had full logic control. In addition you can plug a pair of headphones and listen to tapes directly off the deck as they were being recorded. I used to use it as a fixed ‘reverb’ machine to make jingles and my friend who was in a pub band at the time used it with his microphone to add a bit more to his ‘vocals’, he eventually bought a WEM Copikat, which could do a lot more than a simple tape deck! After visually checking the internals for the usual suspects, I switched the deck on, and the rewind spool started to immediately operate. I initially thought that the logic control board was faulty, however operating the play button and seeing the heads come forward as if to play the tape, revealed that the logic board seemed to be working fine and that the problem was a mechanical one. After a few more tests, it turned out that the two drive belts were too stretched and were not applying the necessary pressure to prevent the rewind spool from rotating. The flywheel on this machine operates at switch on to enable a very quick change from play to fast forward and back to play, as it has a programmable music search function that detects the gaps between tracks to enable you to play, say the third track. The play heads are in contact with the tape whilst the mechanism fast forwards the tape, counting the gaps and playing your chosen song. A new set of belts cured the problem. Luckily the old belts did not turn into a sticky, gloopy mess. A quick clean of the fly wheel perimeter with some IPA before re-assembly and a drop of sewing machine oil on the spindle bush, was all that was needed. Attention was now turned to the Vacuum Fluorescent Display tape counter which was blank. A few voltage checks revealed that the logic chip (HD38755A) and the Futuba (4ST-01ZS1) display were receiving their correct voltages. The next check was that the logic chip was receiving clock pulses from the crystal resonator CT TCH. Expecting to find a 400kHz clock pulse, a very distorted 50Hz wave was seen on the ‘scope. A rummage through my junk box found a 300kHz resonator and this replaced the faulty original and hey presto, the display was working as it should do. A final vacuum of all the boards and a removal of the dry and re-application of new heat sink compound to some of the semiconductors was done. Finally the play and record heads were cleaned with a cotton bud and some IPA, and the rubber pinch roller was cleaned with some distilled water. Another piece of electronics saved from landfill/crusher!
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12th Nov 2022, 8:59 pm | #2 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
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Re: JVC KD-D55 cassette deck brought back to use
Well done, good work done, as you say saving it from landfill.
Is the crystal resonator the same/similar to a quartz crystal oscillator ? David |
12th Nov 2022, 9:50 pm | #3 |
Triode
Join Date: Dec 2021
Location: London, UK - Galicia, Spain
Posts: 30
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Re: JVC KD-D55 cassette deck brought back to use
Hi David,
The resonator is similar to the ones used in TV remote controls. It is the all blue component shown in the second photograph.They are slightly smaller than quartz crystals, as they have a ceramic resonant component rather than a quartz crystal. The resonators are not as stable in frequency versus temperature as quartz, but in this application it is not critical. The data sheet for the HD38755A states an external frequency range of operation ranging from 200kHz - 440kHz, so a ceramic resonator within this range, will work.
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If it ain't broke, don't try to fix it!! Last edited by pointsman; 12th Nov 2022 at 9:58 pm. Reason: Correction |
12th Nov 2022, 11:05 pm | #4 |
Heptode
Join Date: Jan 2007
Location: Luton, Bedfordshire, UK.
Posts: 891
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Re: JVC KD-D55 cassette deck brought back to use
I recall those resonators (salmon-pink-coloured ones, IIRC) used to play up in the Ferguson Videostar 3V23/ JVC HR-7700 early front-loading VCR (though usually the former). Good work!
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Regards, John |
13th Nov 2022, 9:25 am | #5 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
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Re: JVC KD-D55 cassette deck brought back to use
Very 80s styling but none the worse for it, handsome set.
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