Monday, June 01, 2020

Fixing random volume on Cambridge Soundworks FPS2000

Back before 2000, I bought a Cambridge Soundworks FPS 2000 in Berkely to go along with my Creative SoundBlaster Live.  To this day I think it was one of the best purchases I made.  The price wasn't too much for the time, and the sound was awesome for the price.  So good was it that I still have it to this day.  

Unfortunately as time has passed it suffered some damage.  I first had to replace the volume connector due to a bad connection, which ended up being easy because it's just a PS/2 connector.  The recent issue was more complicated.  While playing music the volume would randomly go soft, and then eventually roar back on its own.  Given it was a periodic issue I felt like it must be due to an issue similar that what I fixed on my Polk subwoofer. So I took it apart, and wow were there a lot of electrolytic capacitors. 

Here's a partial list:

main board 
c3 + c3a + c3b + c3c + c2a + c14 + + c4c + c4 + c4b +c11 c4a + c3: 1uf 50v
c39: 10uf 35v
c40: 100uf 16vc41: 100uf 25vc42: 220uf 25v
c26 + c25: 470uf 16vc22: 470uf 25v
c42: 220uf 25vc27: 47uf 25v
c33 c30 c28: 4700uf 25v
side board 
c100a: 470uf x4 16vc102: 10uf 35v
c101: 0.47 50v


So I went ahead and bought a "few" capacitors and a tester:








I took my Hakko 808 (https://www.hakkousa.com/products/desoldering/hakko-808-desoldering-tool-6069.html desoldering gun, which makes light work of removing parts, not sure what the best replacement is, perhaps this):

w
ent ahead and opened it up and found this little guy (C42) in there that looked suspicious:





You'll note the top of the capacitor has a small hole and some yellow gunk.  Also suspicious in that it's a different color than most of the other capacitors.  I put it in the tester (I have to say this little guy is really neat) and measured this:



This guy is supposed to be 220 uF and not pF so something is very wrong with it.  I went ahead replaced it, put it all back together and success! :) Hope this helps someone!

7 comments:

Alex Mohr said...

as an update it seems like this issue still persists :(

Doug said...

I own 2 sets of FPS2000 and both have the same random volume issue. The volume control potentiometers have gone bad and need to be replaced. I ended up building a new volume control using 2 10K potentiometers and a switch that I had on hand.

Doug said...

Here are some photos of the replacement volume controller that I built: https://photos.app.goo.gl/SsF2tsdTDPwFU7nT7
I actually like my controller better than the original because the power button is stand-alone. The volume stays in the same position when I turn it off/on.

timucin edman said...

How did you solve the controller issue? It is similar to ps/2 old mouse connector. My problem is that I cannot get volume for rear spekers. The balancing is not working. There are some schemes on the net to by pass it but I am not a handy man. Any suggestion?

K-PAX said...

I fixed volume controller by these parts for FPS2000.

Montreux Dual pot B50K/B50K CC
Super min toggle switch / Miyama electric MS-243(or MS-600-KB,MS-610K)
MONTREUX / Dual pot Knob
3/8inch Lock washer
Plastics case:W50 x H28 x D80 (mm) *It is necessary to process it.

I changed Woofer Unit.
FaitalPRO 5.25inch Woofer 5FE120-8

Speaker cable
Canare 4S6

FPS2000 connected to Audigy2 ZS by digitaldin cable (4P mini jack and 9P mini Din plug).
It's very clear sound..

Reference materials
https://drive.google.com/drive/folders/1ovL2b5wHQfNmCdp8rEk6igCW2mUsHE1n

Rémi Kébékoua Lacroix said...

I have exactly this speaker system, quit the best ever I had, Still have it but, same problem has yours, volume button broke, I tried to fix it but did not work out, sad 'cause everything still in great shape. If anyone interested it is for sale. to reach me by Messenger at : https://www.facebook.com/Kebekoua/

Alex Mohr said...

ok I think I actually finally fixed it, I found the POT from the control on aliexpress: alpha rd912dsf-20 https://www.aliexpress.us/item/3256803389182737.html. After putting it in it seems like the issue is fixed!