There's nothing obvious so far, the voltage drop in REC is normal given there's more current draw in this mode. I would assume you don't have an...
It's an LA5524, seen this IC in a couple of other walkmans although not the most common. I think the drive transistor is also integrated into the...
There is no risk in measuring these 2 voltage rails. You don't need to touch the CX20084 to do these measurements. See picture attached for...
If RV601 doesn't change the speed with solder bridge open, that indicates a fault inside the CX20084. Assuming that's the case, there's nothing...
Yes, the regulation circuitry is on the motor board. Seen that before motor + servo being treated as a single unit by the service manual. One...
Yes, 3kHz is good enough for speed ajustments. At a higher frequency, despite there is more resolution available there's also more variation. In...
Interesting. There is no abnormal mechanical sound without a tape. With FixYourAudio test tape W&F is jumping quite a bit, with peaks reaching...
Yes that is correct, higher frequencies have a smaller "footprint", that's the reason head azimuth and tape path alignment in general affect the...
Yes your guess is correct the auto-off circuit seems fine no need to check those 2 caps. The voltage at pin 9 rises the same as before, right ?...
Can you do a WFGUI reading of the W&F for both PB (with a known-good 3kHz tape) and this tape recorded on the unit ? It does sound like W&F and I...
Regarding pre-recorded cassettes speed, yes it's indeed unlikely to be off by a significant amount. It's just that (unlike a test tape) we don't...
Yes I forgot there were 2 versions of this mech: AR20 and AR21. Thanks for pointing that out ! Corrected the previous statement. To me the AR21...
One interesting thing is how Panasonic gave the model numbers on these walkmans. This AR21 mecahnism is typical of RQ-X series (which all use...
Looks much better than before, but that W&F is high. Recommend doing 2 things: - oil the front bearing of the motor if you haven't done so...
As far as speed adjustment goes, if you use a song you know well, you can get within +/-10Hz just by ear. But there's another variable that has...
Don't think you understood how to do the test. We're interested in the voltage WHEN (at that exact point, not after) the motor is slowed down by...
You can isolate the fault by removing R616. See if the voltage at pin 9 keeps raising even with that part of the circuit completely disconnected....
D701 is a 7.5V zener diode, used as a voltage reference in the DC-DC converter circuit. However thid DC-DC only powers the PLL, so it's easy to...
These older units almost always use the 13 x 8 x 2mm for the pinch roller: https://fixyouraudio.com/product/pinch-roller-13x8x2mm/ C clips are...
Regarding rubber tires, getting these from a donor unit is not a good idea as it will have similar age and rubber will be degraded to a similar...
Separate names with a comma.
