Repair of a 1940's Decca model DP16 78 RPM record player - part one скачать в хорошем качестве

Repair of a 1940's Decca model DP16 78 RPM record player - part one

Here's part two:    • Repair of a 1940's Decca DP16 78 rpm recor...   Here's an early '40's(?) Decca tabletop 78 RPM record player that someone asked me to repair. This model uses a very heavy crystal pick-up cartridge and tonearm that tracks at around 90 grams (that's right, 90 grams). The amplifier is a single-tube amp, using a type 70L7 tube as both the amplifier and the rectifier. With this design, it's necessary to use a high output 3V crystal cartridge because there is no preamp stage. This same basic amp design, in some form or another, was used in cheaper record players from the '30's all the way up until production of tube record players ended in the early '70's. This amp uses two .02 uf capacitors, one in the plate circuit of the output tube for tone compensation and the other between the chassis and circuit ground to help isolate the chassis from circuit ground. Both capacitors were made by Micamold and were very leaky. Also, every carbon resistor in the amp was way out of tolerance. The amp is now working and passes a fairly stout "hum test" (for a one tube wonder) when touching the input of the volume control. In the next video, we'll deal with the drive mechanism. This will include cleaning and lubricating the mechanism, repairing the idler wheel, etc. Another thing I'd like to address is the tonearm. I really don't like the 90 gram tracking pressure; but, this tonearm has no provision to adjust the tracking pressure (there's not even a counterbalance spring). If I were to use a modern ceramic cartridge, the tracking would still be much too high for the new cartridge; so, I'm going to attempt to add some sort of counterbalance spring. If that's not possible, the only other option is to have the old cartridge rebuilt. It goes without saying that the records will like it better if I can get the weight down to 10-12 grams. The speaker is also shot and I could replace it with a modern chinese speaker; but, a new speaker is not as well made and will not likely sound as good as the original Magnavox speaker.