Thank you for providing such helpful high quality videos about our beloved oldies! I also got a 122MKII from a broadcaster some years ago and of course had to change idler tiers, the belt, and capstan board caps. I also replaced C134 and C136 next to the mainboard's red power supply socket for the control board. The 100µ had only 40µ left and both were mounted with wrong polarity straight from the factory. Also the labelling on the PCB is wrong. The result is slight hum and a strange behaviour of the counter - especially when you insert a cassette, due to the current peak when the capstan starts rotating. My deck also has another issue: during PLAY the MECHA motor tries to lift the headblock to the tape tough it is already on the top position. The comparator voltage on U507 never gets so low that the motor stops spinning. Probably someone put the plastic joint on the 10k pot delivering the voltage proportional to the headblock height at the wrong position (the pot itself is fine). Maybe a 122MKII owner is able measure the voltage on P503 pins 1 and 2 during PLAY (which is the voltage for the MECHA motor)? I'm curious whether it's really 0V or whether the designers wanted to give the motor a litte torque during PLAY so that the mecha block is guaranteed to be fixed at the top position. On tapeheads.net / Cassette I put a topic with a photo where to find U507 and P503. Thank you again 👍👍👍
Thank you for watching. Once the control motor rotates the cam to the correct detent, it no longer requires voltage. Maybe you have an issue with the trimpot adjustments. The procedure is well documented in the service manual.
Thank you for your quick response! According to your statement I will align the joint so the motor gets 0V at play since I can't find any other errors in the electronics. All the relevant measured voltages are in accordance with the calculated ones based on the service manual. The trimpots effect the height for the other operation modes only, except for the stop position, which has a little influence on the play position. The "play-voltage" is more or less fixed and is determined by R540 (470R) in parallel with the stop-voltage-setting (R543+RV547) which is at least 2k7 (and R548, 5k6 of course which is the other end of the voltage divider). Keep providing us with such great videos!
Hello Peter! Yasou! The device produces very good results! In fact, this is not much distortion at such a high overdrive recording level! Continue to amaze with such interesting videos! Thank you!🤝🤝
Not at all, I see them on eBay frequently. You could also make your own with a little effort. I've used front-silvered mirrors from old scanners, they work well.
@@asbcustom That's in par with a semi pro reel to reel machine, Not sure what number you're looking for? What is the lowest W&F ever recorded or published on a consumer cassette deck?
Oh no that's not a complaint, my children know that "satisfactory" from me is high praise, I have very high expectations. These are considered professional machines, and .04% is the published spec., so I'm satisfied with it.
Amazing! I am in awe of your work and grateful you take on this work. Looking forward to putting it back in service!
Thank you, I look forward to your evaluation.
Watching! Just letting you know :)
Thank you for providing such helpful high quality videos about our beloved oldies! I also got a 122MKII from a broadcaster some years ago and of course had to change idler tiers, the belt, and capstan board caps. I also replaced C134 and C136 next to the mainboard's red power supply socket for the control board. The 100µ had only 40µ left and both were mounted with wrong polarity straight from the factory. Also the labelling on the PCB is wrong. The result is slight hum and a strange behaviour of the counter - especially when you insert a cassette, due to the current peak when the capstan starts rotating.
My deck also has another issue: during PLAY the MECHA motor tries to lift the headblock to the tape tough it is already on the top position. The comparator voltage on U507 never gets so low that the motor stops spinning. Probably someone put the plastic joint on the 10k pot delivering the voltage proportional to the headblock height at the wrong position (the pot itself is fine). Maybe a 122MKII owner is able measure the voltage on P503 pins 1 and 2 during PLAY (which is the voltage for the MECHA motor)? I'm curious whether it's really 0V or whether the designers wanted to give the motor a litte torque during PLAY so that the mecha block is guaranteed to be fixed at the top position. On tapeheads.net / Cassette I put a topic with a photo where to find U507 and P503.
Thank you again 👍👍👍
Thank you for watching.
Once the control motor rotates the cam to the correct detent, it no longer requires voltage. Maybe you have an issue with the trimpot adjustments. The procedure is well documented in the service manual.
Thank you for your quick response! According to your statement I will align the joint so the motor gets 0V at play since I can't find any other errors in the electronics. All the relevant measured voltages are in accordance with the calculated ones based on the service manual. The trimpots effect the height for the other operation modes only, except for the stop position, which has a little influence on the play position. The "play-voltage" is more or less fixed and is determined by R540 (470R) in parallel with the stop-voltage-setting (R543+RV547) which is at least 2k7 (and R548, 5k6 of course which is the other end of the voltage divider).
Keep providing us with such great videos!
Thank you and good luck!
Hello Peter! Yasou! The device produces very good results! In fact, this is not much distortion at such a high overdrive recording level! Continue to amaze with such interesting videos! Thank you!🤝🤝
Yasou Vadim! Yes, and even more impressive is the fact that most of these have spent their whole lives in daily abuse!
This fact once again proves that the professional Tasсam line is simply top notch 👍💪@@asbcustom
So you put actual audio tape in your mirror cassette...these things typically have a green coloured film strip in them.
I did not, it came to me this way. I think it's a good thing though, I'd rather observe how an actual tape performs rather than an uncoated film.
I like the mirror cassette. Are those hard to come by?
Not at all, I see them on eBay frequently. You could also make your own with a little effort. I've used front-silvered mirrors from old scanners, they work well.
Do you back lap heads and service other cassette decks😊
I'm familiar with back lapping but unfamiliar with how it applies to tape heads?
0.04% is incredibly low.
It's a satisfactory number, yes.
@@asbcustom That's in par with a semi pro reel to reel machine, Not sure what number you're looking for? What is the lowest W&F ever recorded or published on a consumer cassette deck?
Oh no that's not a complaint, my children know that "satisfactory" from me is high praise, I have very high expectations. These are considered professional machines, and .04% is the published spec., so I'm satisfied with it.
@@asbcustom No worries.
Greetings! Look at the detonation of my Tasсam 112 mk2... It has one capshaft!
studio.czcams.com/users/videoQ-GjDNG82n4/edit