Parts Question Repairing amp for cambridge sw bascube 12s

[Frankfla]

Parts Question Repairing amp for cambridge sw basscube 12s

Hello,
Well my subwoofer went out, reading around found info on how to repair so I opened up and found this
**broken link removed**
What I expected based on what I had read, caps bad and took resistor and diodes.
I have the diodes figured out. Question on the caps and resistor.

The caps I found are rated at 2000 hours@ 85c . I had read something about the original one being cheap and using better replacements. Is that good enough to use?

The resistors are really giving me problems.
**broken link removed** The resistor is the one on the left starts at the one inch mark
The color code is red black red gold . I think that is 2k ohms. When I put a meter on them one reads 1.4k and the other about 1.2k . There is a larger one marked 1k ohm and it reads right on.
So am I right that the resistor is 2k ohms and the bigger question how do I tell the wattage of the resistor?

I found the caps and diodes at digikey but no such resistor are there any better sources?

Thanks for any assistance!
Frank

 

[Nigel Goodwin]

You need to take the resistor out of circuit to measure it, it may well read low in circuit.

The caps you found should be fine - it's not easy to find 105 degree large electrolytics.

 

[sparkman001]

The resistor looks to be a 2w metal film, but could be a fusible type, its difficult to tell from the photo. If its red/black/red/gold it is 2k ohm 5% tolerance. So as youve been informed unsolder one end and re-check the resistance and it should read 2k ohm +or - 10ohms, if its ok put it back in. The electrolytics are cooked, replace them both together with the correct diodes, then check all the other components in the power supply and if they are ok you should have a working unit. You havent said where you are based but if you cant obtain 2k 2watt just use 2 x 1K ohm rated at 2watt connected in series.

 

[KeepItSimpleStupid]

I'll vote for 1 to 2 W metal oxide.

 

[Frankfla]

Thanks for all the help. Found all the parts and they are on the way!

 

[Frankfla]

Ok got the parts replaced all four caps, two resistors and 2 diodes. Plugged it in good no smoke or sparks, hooked it up, good sound for about a minute then it stops. Unplug it resets works for a minute and quits. I know it is broad question but any ideas what I could have done wrong?

 

[KeepItSimpleStupid]

What voltage do you have across the two largest resistors next to the heatsink as it's warming up?. They look like 0.22 ohm.

How hot are the transistors and the heatsink?

Is the thermal switch changing state?

Another useful number is the voltage between the bases on Q6 and Q7?