Powered mixer repair – Wharfedale SPX815

powered mixer repair wharfedale spx815 powered mixer

Just doing a quick write up of a powered mixer repair that’s going out today. It’s a Wharfedale repair, an SPX815 powered mixer that had no sound output from the left output channel.

My first instinct when the Newark customer contacted me was to expect that the output stage had blown, but this turned out not to be the case as I quickly discovered that the left channel was fine when a signal was plugged straight into the power amp inputs.

Powered Mixer repair Wharfedale SPX815

Powered Mixer repair Wharfedale SPX815 - botched wood screwIt’s difficult to attempt a powered mixer repair without schematics so I’m very grateful to the gentleman on a forum who sent me the schematic over. After tracing the fault through the schematic I discovered that an SMT op amp in the left channel graphic EQ was blown – there was a nice neat hole in the top.

Someone had already attempted a repair on the PA section of this amplifier – I’ve no idea what they were doing, but they’d bent the metal chassis around the PA, stripped the threading on a PEM and tried to hold the whole botched job together with a wood screw. It’s pretty much impossible to bend things like this back, but I did my best, redrilled the mounting holes and replaced the dodgy wood screw with a machine screw! I left a note to any future repairers so that no-one things the dodgy work was done by was me!

Here’s a video of the powered mixer repair:

If you need a powered mixer repair, please get in touch.

PA speaker repair – dB Arena 10

pa speaker repair

Last year I completed a PA speaker repair, I’ve just found the photos of the damaged crossover so I thought I’d blog the repair.

The owner had bought a pair of these nice dB Arena 10 speakers from a disreputable eBay seller. One was working, but the other had a fried HF compression driver and a damaged crossover.

Fortunately the 1 inch dB compression drivers are commonly available from the likes of Thomann so this was easily replaced.

A resistor had also burnt out in the crossover so I replaced this with a higher spec part.

Upon completion I graphed the frequency response of the crossover and compared it with a known good unit.db arena repair

If you have a Pa speaker repair, please get in touch.

PA Repair – Prosound 1000

PA Repair

This PA repair, a Pro Sound1000, was brought to me with a couple of reasonably common symptoms. One channel was producing no output, the other channel was very quiet. To be honest I’m surprised that the internal fuses hadn’t blown. The symptoms pointed towards what is probably the most common problem with solid state PA repairs – several of the output devices were short circuit in one channel. This affects the shared supply rails of the power amp, which probably caused the effects in the other channel. I replaced the transistors from the faulty channel and both channels ran fine.

Whilst fixing the amp, I noticed that the reservoir capacitors were leaking, so these were replaced as a precautionary measure to prevent future damage.

If you have a PA repair that needs some attention, please get in touch.