Evening all,
Got a little problem here and getting nowhere...

I have have two DD1s here, one to repair, the other one for spares. Problem is the one I'm refurbishing is not making any sound at all, no humming, no buzzing! I did everything I could imagine, even took the circuit board out of the other one and put it in...still nothing.

Funny thing is, I do know now that both PCBs work just fine. Question is: The only thing left to check is the head. Can a dead be responsible for no sound at all???

I'm frustrated....

Cheers!

Good evening Sajin!

That is very interesting and sorry I can't help you. When it comes to DD walkmans, I am helpless and wouldn't wanna suggest you something that'd be damaging to your DD so I will recommend you contact Agent orange or Rencgi who have enormous technical expertise in the DD walkmans.

the only thing that comes into my mind is that you check the head of the unit and see if all the wires are soldered where they should be underneath the head itself. Maybe the head itself is dead and gone. Is there any power in the unit and are the reels spinning?

I am figuring this stuff myself yet...

Hey man, thanks for your input.

I'll try to be a little more precise:

Everything works as it should, I replaced a few parts and the machine is running smoothly.
I de-soldered the original PCB and put it in my second unit. I thought there was something
wrong with the electronics on the board...but I was wrong. The board is fine and works
in my other unit.

I just checked if it would kill all sound if I unplug the head. But it doesn't...
Even with the head unplugged you still get something out of the headphones.

So, everything is working as it should, just not in the DD1 I'm fixing....damn.
I mean, what else can it possibly be??? It's really beyond me...

Hmm... So you desoldered the pcb and put it onto an another unit and it works but it doesn't on the unit you are fixing. That is very interesting (not to say sad actually). So everything must be okay with the pcb which would mean there is a problem in themechanism itself or in the wiring.

One time I couldn't start a tractor because it wasn't getting the power it needed from the battery to start up. The wires were all seemingly intact but in one wire the actual copper inside was broken and lost contact. I couldn't see it because the plastic isolation was not damaged in any way. I know this is funny but if you haven't already, maybe you should try replacing the wires with which the pcb is connected to the rest of the chassis. I don't know what else to say. Either that or thre is a problem with the mechanism although I can't possibly imagine what that might be. Sorry, i am really lost when it comes to DD units.

I repaired couple of more modern Panasonic players which took me forever but now they work perfectly. With Panasonic there are no wires. the pcb is soldered directly to the chassis.

What do you think? Could it be the wires?

Hi Tuna,
I doubt it's the wires. Thing is, I can hardly imagine
that any components not sitting on the PCB are responsible
for the total lack of sound. I mean, the motor works just fine,
you will get sound even if the head is unplugged (or damaged for
that matter) and the mechanical parts cannot be the problem at all.

The only thing I'm left with is the servo, as it's the only
component I have not checked yet...

But then again, the servo controls the motor and should not
be affecting the sound after all. Right? Or wrong? Hm...

This is getting more bizarre by the minute

quote:

ut then again, the servo controls the motor and should not
be affecting the sound after all. Right? Or wrong? Hm...

This is getting more bizarre by the minuteSmile

Yeah it's logical. Servo controls the motor and I don't see how that would be the cause. I am clueless...

On my first repair, I accidentally torched one of the circuit chips on the pcb of one of my walkmans and when i finished with the mechanical repair, I installed it back and it didn't work. Eventually my friend tested it using his instruments and found the cause. But that can't be the proble because you tested it on an another unit...

It is really puzzling me. Have you contacted AO about it?

Bad orange capacitor, to the servo motor control IC had the same problem, same unit no sound, or when there was sound alot of noise was heard and servo motor speed was alot slower and sometimes fast. I replaced the orange capacitor and the yellow capacitor, unit now works great. Speed is what it suppose to be, those caps are by the out to the servo motor leads

Do have a spare DD1 that I not using case is damage and head is gone but PCB works and transport still works fine, just not worth rebuilting because of the case, but good for parts.

I got a case of old DDs this morning including two DD1s. Will follow your advice and try to change the caps. Thanks!!!

Tried a third board, getting sound now. Unfortunately just a high pitch squeal....

Is this a PCB related problem or is it the head dying?

If it's the board, is there a component prone of quitting its service after a while? Anything that might be fixed?

Bad preamp IC?