Hi
I have recently restored two Sony Mini-Hifi combos.
(TC-H5900 Deck TCM-190R Mechanisms also used on other decks)
Cleaned Lubed & replaced the dreaded tape take up clutch cracked reel.
I fitted also new belts & pinch rollers.
The CD pick-up & belts were also replaced.
All functions work OK & sound is also fine.
On one of the deck units, on deck B when playing a cassette the motor starts faster say 5% but after a minute or so stabilizes to correct speed.
I managed to calibrate it with a 3KHz (Bought Online) calibrating tape when speed was stable, and have a time mismatch with same type of tapes between the decks of 15-20 seconds (C60 Type). Wow & Flutter was measured with WFGUI & was also OK.
The motor is 4 wire Type and is controlled by 2 transistors. One for On / Off & the other for H/L switching, according to the schematics.
I could switch the motors but I don't want to disassemble it one more time and I can live with it.
Has anyone faced the same issue before & found the culprit ?
Thank You for Your attention
I have recently restored two Sony Mini-Hifi combos.
(TC-H5900 Deck TCM-190R Mechanisms also used on other decks)
Cleaned Lubed & replaced the dreaded tape take up clutch cracked reel.
I fitted also new belts & pinch rollers.
The CD pick-up & belts were also replaced.
All functions work OK & sound is also fine.
On one of the deck units, on deck B when playing a cassette the motor starts faster say 5% but after a minute or so stabilizes to correct speed.
I managed to calibrate it with a 3KHz (Bought Online) calibrating tape when speed was stable, and have a time mismatch with same type of tapes between the decks of 15-20 seconds (C60 Type). Wow & Flutter was measured with WFGUI & was also OK.
The motor is 4 wire Type and is controlled by 2 transistors. One for On / Off & the other for H/L switching, according to the schematics.
I could switch the motors but I don't want to disassemble it one more time and I can live with it.
Has anyone faced the same issue before & found the culprit ?
Thank You for Your attention
Last edited:
Try posting in this forum. Lots of cassette experts there.
Cassette - Tapeheads Tape, Audio and Music Forums
Cassette - Tapeheads Tape, Audio and Music Forums
I see you are not getting much attention at Tapeheads...
The speed is controlled by Q601, Q602, Q603, Q604, Q605, Q71B. All the required voltages for either speed, are labelled on the diagram, so it should be a meter of systematic approach and careful measuring that will lead you to a root cause.
That 9.1V zener (D602) should be replaced before you start with anything else.
Look for PCB discoloration, signs of heat damage; look carefully for little cracks in soldering...
Good luck,
Nick
The speed is controlled by Q601, Q602, Q603, Q604, Q605, Q71B. All the required voltages for either speed, are labelled on the diagram, so it should be a meter of systematic approach and careful measuring that will lead you to a root cause.
That 9.1V zener (D602) should be replaced before you start with anything else.
Look for PCB discoloration, signs of heat damage; look carefully for little cracks in soldering...
Good luck,
Nick