Advice on recapping - Telefunken W690 faders

[flextone]

Alright so I opened up the second w690 and it looks rather different in there, nice and shiny. Am I right in thinking that this one has already been recapped and I should leave it alone for now? It is working properly and the stamp says "gepr. 11" (which I assume means tested 2011).

Pictures:

 

[Bo Deadly]

Nope. That thing is straight out of the 1960's. Again, personally I would just recap the whole thing.

More specifically, I would take good photos of both sides. Manipulate the photo of the underside to be high contrast and then print it out. Then carefully go though and mark each cap location with a + sign to indicate polarity. Then check polarity again. Then find someone with a hot air station (or even buy one - they're not super expensive and they're a great tool) and ask them to carefully remove all of the electrolytics and tants. Then order axials for the two big electrolytics and radial electrolytics to replace all of the tants. Size and voltage should be same or next size / voltage above.

 

[mjrippe]

Tested (or inspected) by Number 11. Not a date code.

 

[flextone]

Ok, was just wishful thinking. One last question before I start buying the parts.
What are these three anomalies on the board? Might be a problem identifying the values for them. I can't figure it out from the schematic.

Thank you!

 

[rock soderstrom]

Ok, was just wishful thinking. One last question before I start buying the parts.
What are these three anomalies on the board? Might be a problem identifying the values for them. I can't figure it out from the schematic.

Thank you!

View attachment 81046

A is a inductor/ coil, no need to replace
B is capacitor, no need to replace
C is a trimmer, a variable resistor (R121 - 18k), no need to replace

 

[flextone]

I see.

How should I understand the difference between the two faders? The first one I showed you has 10 tantalum and 2 axials. The second one also has two axials but 9 tantalum and 3 of these rectangle caps. Weird

 

[dmp]

The second one is very different. It looks like a different layout with different component numbering. And it doesn't follow the schematic I posted.
Can you post a side picture showing the whole thing and the faceplate?

 

[rock soderstrom]

No, not really weird. These units were produced in high quantities over a long period of time, normal production variations.

 

[dmp]

Actually now that I'm looking at the schematic I'm not sure which version the schematic is correct for. I have a W690 here that is like the first one you posted, and I don't see a trimmer on it. Your second one has C109 as a small tantalum cap, but it is a 1000 uF in the schematic.

 

[flextone]

The boards are definitely different, although they have the same number printed on them. Serial numbers are far apart, but they are both W690s. I can take better shots of the components tomorrow during daylight.

 

[dmp]

They redesigned the PCB but didn't change the ID number on the etching LOL
Mine is exactly the same as your lighter colored board except it has a silver front panel. #1439
I'm guessing that is the one with the lower number on the front panel?

 

[dmp]

It looks like the audio section is pretty close to the same and they redesigned the power filter section.
Mine has 22uF in place of 15uF in two places. But if you order the polarized caps off the schematic you should have what you need.
I personally would not sub electrolytics for the tantalums in the audio path.

 

[flextone]

But they have a different number of tantalums, and one has those rectangle shaped caps in it. Should I just stick to the schematic nontheless?

I think this is a bit much for me, it's too dense in there. I will either get someone to desolder everything for me or do the whole thing if the price is right. I do want to purchase the parts myself though.

 

[flextone]

Hi,

I'm finally making a list of the polarized caps to buy. I'm having a problem locating a 100 µF / 3V tantalum. Would a 100/16v be ok instead?
Also, I'm not very calm about the 20% tolerance on the 15 µF caps. It's the only one they have currently, and no higher voltages. Any advice on this?

Here's my shopping cart so far:



I'll try a few other shops as well.

Thanks!

 

[Bo Deadly]

Yes, 16V is fine. But you really don't need tantalums. Tantalums are used when you need super low leakage which is almost never applicable in audio.

 

[flextone]

Cool thanks. Well I don't need a lot of parts and it's not expensive, so I rather stay as close to the original as possible,