Reel 2 Reel Trio Part 2 JVC Nivico TR541 Vintage Tape Recorder 1966 (4K)
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- Опубліковано 20 вер 2024
- Video diary working on the JVC TR541. This video was stretched out over 11 month filming period. Daz has fun with germanium transistors again and a replacement pinch wheel was called for. The Tape I was using also came back to haunt me. Music from UA-cam Audio Library. Warning:- Mains/line powered equipment contains high voltages that are dangerous to work with.
My dad used to have one like this. When I broke it at the age of 2 (my first cassette player), my aunt gave him hers. I broke that one too. :) One was white, the other was black. Watching this video took me back to my childhood. Thank you. Now I know what it's called and can try and look for it :) I also remember it had a microphone attached to it with a cord.
Nice to see you back Darren.
Thank you. I'll try to keep the videos coming.
Another interesting and informative restoration video. Nice to see you back.
Thank you very much. I'll try to keep the videos coming. Daz
Funny that they went to the extra cost of AC bias for the head then used DC for the erase. Would have been almost the same cost to use the same AC bias circuit also for the erase head. Would have lowered the overall noise in erase quite a bit.
Its a bit strange as possibly a heat sink only would be needed for the extra current, Michael. Im not sure if it has anything to do with reducing the power consumption on battery perhaps? At least AC bias thankfully. Daz
We will all get older and greyer along with you Darren lol. I use Russian Transistors In my transistor radio restorations .leakage current is lower. Still trying to find a good substitute for the AF117( tin whiskers ) just a ps Techmoan uses draft excluder the felt with the sticky back .I can just see the grey hair starting to appear 😫
I think I used the russian 322 in my bush TR82C radio to replace the AF117. I had to sort through to find higher gain ones. Oh yes, I forgot about the draft excluder, I have some I used for 8 tracks! Thanks for watching, Daz
The pinch rollers (goldilocks and the three pinch rollers) only one is just right :-D
You have improved that no end, the recordings have body now.
Yep germainum transistors are crackers, i used to call them Geranium.
My brother hated that as he was a ham lol.
I like a meter and level pot for recording, or a magic eye as they are nice 😀
Nothing like a visual indicator to add interest for sure. A lot better with the new transistor. Its surpising how some transistors are still fine after many years and others leak like a rusty bucket! Daz
I have a Phillips unit I need some belts for but there's no model number on it.
Thats annoying, Michael. Sometimes the paper model sticker falls off philips stuff. Also they like hiding it on the chassis somewhere or near the voltage selector. I have had to google a make and select images before to identfy a model of radio, time consuming, but it i got lucky. Radio Museium Ive found usefull as can seach a make. Daz
@@darrencoe5795 I need to do some research but as you say very time consuming as the net is such a big place now .Many thanks .
U OK wondering when your posting again regards shaun
Hi Shaun, I haven't got anything together at the moment. Many unfinished videos I am afraid. I don't have much time at present. Daz
@@darrencoe5795 hi Darren no worries just checking that you are ok regards shaun
@@shaunsiz.itsbetterbytube2858 Thanks for asking, Shaun
Another interesting video on a machine which would have fairly quickly been overtaken by the cassette revolution. Just a few years from this one and the Japanese manufacturers will stride way ahead of the European and American manufacturers in the quality and value for money of their reel to reel machines as with all their domestic electronic equipment.
One comment though on your electronics repairs. Your capacitor tester shows most of the electrolytics having, at least, doubled in value. In practice, I doubt this very much. By their nature, they are electrochemical devices and have a degree of leakage across the dielectric. With time, they degrade and the leakage increases. A tester such as you are using measures the time taken for the voltage across the capacitor to reach the measurement threshold. As leakage resistance decreases, so the time taken to reach the threshold test voltage increases since charge is leaking away faster. Thus the meter senses this longer duration as increased capacitance. The only way by which the actual capacitance can increase is by thinning of the dielectric layer, which is extremely unlikely. Any thinning will reduce the voltage handling of the capacitor and it would almost inevitably breakdown the dielectric and go short circuit. In practice, the outcome is the same, as any leaky electrolytic will mess up the biasing of the transistors and it needs replaced.
Because of the very variable nature of electrochemical dielectrics, the capacitance is always a bit 'suck it and see' though manufacturing quality control has improved things a lot in the past 50 years. Good manufacturers will measure them after manufacture and mark them in accurate value bands. Cheaper products will often show the values on the specification sheets with tolerances of +100% and -50% though as they skip the costly testing stage.
By contrast, polyester mica and other solid dielectric capacitors approach being 'perfect' capacitors with effectively zero leakage but are impractically large for higher capacities due to the thicker dielectric layer. This has improved over the years, however, which is why for quality work, polyesters are often used up to the low microfarad ranges. Solid dielectric capacitors only tend to leak if there is a breach in the insulation coating allowing moisture ingress.
Just a bit of input and clarification from a retired professional Physicist/Chemist/Electronic Engineer/Video Producer.
Keep up the good work, Darren.
Indeed, The Japanese equipment was very much the king of affordable HiFi. Of course I think streaming has really dented Hi-Fi for the masses. Shops seem to stock bluetooth speakers and DAB radios in the most. Thank you for pointing out the leakage issue and meters. I am currently trying out a few experiments with different meters. Daz.