These were used in my high school electronics class. A number of different kits were available. With todays safety regulations and lawsuits you wouldn't see anything like this now because of it being line operated and no isolation transformer (although our classroom had isolation transformers which the instructor insisted we use). But these were great training tools for the day and led to my career in electronics repair.
No, unfortunately these Japanese Graymark kits were from the 60’s and were made for students taking the training course. It’s very hard to find one today, even the built ones. This kit was sent to me by my son who acquired it from an estate sale. Even this kit was picked through because it was missing all the capacitors, resistors, hardware, manuals and assembly instructions. Thanks for watching my video and your interest.
Sure, I did the second video in part 2 using the Graymark schematic only, in my previous video I used an unknown schematic which required just the 1st IF and there was no 2nd IF in this schematic. I then wired the primary of the included 2nd IF transformer that was in this kit up as the coil as per this unknown schematic. There was also the questionable possibility of a plastic enclosed tuner and the opened type of tuner. That unknown schematic was also not showing the coupling capacitor wired to the cathode and the plate of the output tube. I viewed a Magnavox schematic (also shown in the Graymark schematic) to get the correct value of this coupling capacitor. I wanted to show the same audio quality with wiring a 2nd IF transformer primary as a coil only and then wiring up both the primary and secondary as per the Graymark’s schematic. Hope that makes sense, this is a learning project kit, and my objective was to mix it up with the 2nd video. Thanks for watching and I hope that I cleared this up for you.
These were used in my high school electronics class. A number of different kits were available. With todays safety regulations and lawsuits you wouldn't see anything like this now because of it being line operated and no isolation transformer (although our classroom had isolation transformers which the instructor insisted we use). But these were great training tools for the day and led to my career in electronics repair.
Is this kit available, or is it a one-off that you found? Thanks.
No, unfortunately these Japanese Graymark kits were from the 60’s and were made for students taking the training course. It’s very hard to find one today, even the built ones. This kit was sent to me by my son who acquired it from an estate sale. Even this kit was picked through because it was missing all the capacitors, resistors, hardware, manuals and assembly instructions.
Thanks for watching my video and your interest.
You say "unknown schematic" but are using the Graymark schematic. Please clarify.
Sure, I did the second video in part 2 using the Graymark schematic only, in my previous video I used an unknown schematic which required just the 1st IF and there was no 2nd IF in this schematic. I then wired the primary of the included 2nd IF transformer that was in this kit up as the coil as per this unknown schematic. There was also the questionable possibility of a plastic enclosed tuner and the opened type of tuner. That unknown schematic was also not showing the coupling capacitor wired to the cathode and the plate of the output tube. I viewed a Magnavox schematic (also shown in the Graymark schematic) to get the correct value of this coupling capacitor. I wanted to show the same audio quality with wiring a 2nd IF transformer primary as a coil only and then wiring up both the primary and secondary as per the Graymark’s schematic.
Hope that makes sense, this is a learning project kit, and my objective was to mix it up with the 2nd video. Thanks for watching and I hope that I cleared this up for you.