Tech Soundsystems Black Cat; transformer death x2 this could be terminal... unless

[3below]

@agedhorse mentioned the sloppy wiring / connections earlier Looking at the picture of the board there appear to be quite a few solder joints (of those that are visible) that want investigation / re flowing   (in addition to the transformer connections needing  heat shrink etc.).  An interesting design decision that the bridge rectifier diodes do not have separate pads for the diode terminals and the incoming connections. If you (or someone) replaces the smoothing capacitors this would be the ideal time to tidy things up.   It will be good when it is fully sorted:) 

 

Edited June 20, 2023 by 3below

[warwickhunt]

53 minutes ago, 3below said:

@agedhorse mentioned the sloppy wiring / connections earlier Looking at the picture of the board there appear to be quite a few solder joints (of those that are visible) that want investigation / re flowing   (in addition to the transformer connections needing  heat shrink etc.).  An interesting design decision that the bridge rectifier diodes do not have separate pads for the diode terminals and the incoming connections. If you (or someone) replaces the smoothing capacitors this would be the ideal time to tidy things up.   It will be good when it is fully sorted:) 

 

 

Interesting that you have circled/highlighted several (not all) connections that are original from manufacture.    

 

I did take it to another electrical engineer after the 2nd transformer replacement (I couldn't understand how 2 had failed and no fault found); he had it several weeks before declaring it was fit and made zero comment on any soldering etc. 4 days later that transformer burned out.  I think many of the informed comments made, highlight the difference between the business approach and the professional/informed user insight...  if only some of the business heads actually had an interest in what they were doing.  I'm maybe doing them a disservice as they have to make money and time is money, so going over something with a fine toothed comb is expensive.  At the end of the day I could end up paying someone double the value of the amp to just give it an MOT/heath check.  

[3below]

5 hours ago, warwickhunt said:

......   At the end of the day I could end up paying someone double the value of the amp to just give it an MOT/heath check.  

 

This why I like some older kit, chosen wisely it can be easily self repaired in the event of problems unlike my QSC power amp that totalled itself (switched on at the time but not doing any amplifying!). 

[BassmanPaul]

I have to admit that the wiring shown is absolutely terrible. In my mind a disaster waiting to happen. I still hope that the amp behaves itself! 

[warwickhunt]

Even if I dare not tackle the caps etc I may have a look at aligning the wiring and taking strain off before resolder and shrinkwrap.

[agedhorse]

On 20/06/2023 at 08:34, 3below said:

 

This why I like some older kit, chosen wisely it can be easily self repaired in the event of problems unlike my QSC power amp that totalled itself (switched on at the time but not doing any amplifying!). 

Why wasn't it repairable? Any authorized QSC service center should be able to service this. It's certainly not a self-repair type device, but it was never intended to be a DIY service device with the technology involved.

[3below]

6 hours ago, agedhorse said:

Why wasn't it repairable? Any authorized QSC service center should be able to service this. It's certainly not a self-repair type device, but it was never intended to be a DIY service device with the technology involved.

Cost of repairs - new main board and other parts plus labour / transportation exceeded the cost of replacing it. 

[agedhorse]

Which model?

[3below]

56 minutes ago, agedhorse said:

Which model?

GX 5 from memory, I picked up a nearly new XLS 1502 for far less than the quoted repair cost.

[agedhorse]

3 hours ago, 3below said:

GX 5 from memory, I picked up a nearly new XLS 1502 for far less than the quoted repair cost. 

The GX-5 is an easy amp to repair for a qualified authorized service center.   They have also proven to be extremely reliable over the past ~20 years or so. I don't recall any of the ~100 GX series amps that I had installed ever failing, they were at least as reliable as the RMX amps, but in a smaller  (shallower) package.  That said, the reduced cost of manufacture of some new amps can make them less costly to purchase in some cases.