Hi all,

Does someone know where I can find a replacement potentiometer (volume) for a SA-9900? The potentiometer contains four plates, where one of them is broken. I fixed the plate and the contacts, but prefer more a unbroken one. Replacing with a normal 4 layer potentiometer looks like no option. It seems that the four layers (plates) are not synchronised for the resistance values.
Thanks for advice.

The entire assembly is acv-144 and is only used on the sa-9900 and sa-9500.

Sounds like a problem with the volume control.

It is an acv-144, a dual 50k ohm audio taper pot with NO loudness tap (and 22 detents).

It is used in the sa-9500 and sa-9900

From the circuit hooked up to it, a 100k would work for a test

Are you SURE it is a 4 layer pot????????????? I believe the sa-9900 control has only two wafers.

I just got done dealing with a sa-9900 with a cracked wafer (I had it IN MY HANDS, with pictures posted) in this thread:

http://www.audiokarma.org/forums/showthread.php?t=167230&page=5


Post #74 starts to explore the alternatives,

Why do you think I asked you for the number of detents?..... I have done this before, and anything from a lowly sx-550 volume control: acv-161 (dual 100k, audio taper, loudness tap, NO detents) , sx-550 treble control: acv-138 ( dual 100k,audio taper,no tap, 11 detents) sx-3800 volume control acv-181( dual 100k, audio taper, loudness tap, 40 detents and STILL available from Pioneer ($20.50)) will work.

post #83 on page 6 has a disassembly analysis
post #91 on page 7 is a confirmation that the sx-550 volume control pot acv-161 worked fine in that sa-9900
post #92 s an observation that the standard rotation range of the pot was slightly less than the rotation range of the acv-144.

Bottom line, get the acv-181 NEW (while you can) from Pioneer and put it in, the 3800 was one step down from the TOTL sx-3900 and I expect with 40 detents was held to tighter tolerances between wafers.

Thanks for your reaction.

The repair manual indicates a two layer. The SA-9900 which I have is a European one (220V AC). The model serialnr starts with VL..., so was probably an early model. It is possible that the circuits are changed in time.

I have the impression that all is original (4 layers are connected to the circuitboards via wire wrapped leads). The type indication of the potentiometer is lost, so I don't know the reference nbr.

Measurements on the potentiometer gave different results between the two pairs (but are equal two by two). Visually, I also noticed that the contacts are different for each pair. The end value is 50k.

You can see on the attached photo's the four parts, and less distance between the rectifier circuit then a two layer. I will try to find out where the connections are used for or connected to...

Wow, somebody really shoehorned that in, you have had it out?

And all 4 decks have connections to them? The connections are wires, as opposed to a pc board?

I remember something had a 4 gang volume control, but which model(s) escapes me right now...