Peavey XR696F mixer amp

Owner acquired knowingly non-working off a friend of a friend, so no point in asking him/them what is normal operation. Nothing about the following test routine? in the user manual Reported as ok for practise use but will not switch into high-power gig mode. I've not got inside yet to monitor power rails/ try use dummy loads etc. Low level test signal in, the output jumps to a high level soon after switch on, plus bargraph surge, for half a second and then drops back to low level. Is this normal, just checking-out +/-40V to +/-90V switching of rails is ok? If so why the bargraph jump?

Rant:

There was a time when Peavey had a large facility in Corby, UK. If you wanted spares, you could phone them and anything you wanted would be there in a couple of days. It was an excellent service, one of the best.

Now the Corby Facility is closed. You have to go through a 3rd party, Barnes & Mullins.

Ask for a pot for a particular amplifier, and you have no chance. They have to contact Peavey USA, get a part number, then try and get it across the pond.

Tried that, just doesn't work. Peavey spares are now largely unobtanim, the brand is dead in the UK.

Gareth.

"Gareth Magennis" wrote in news:qKvRy.1223993$ snipped-for-privacy@fx42.am:

However, Peavey service in the U.S. are very helpful with requests for service manuals, and help and advice with obscure problems.

Arfa

Just as well I never use main agents. Got the sections out of the box to work on. Class G PAs with only ch1 &2,signal-in from Prea according to the schema , so whatever is causing the leap and drop back at switch on is in the Prea. A surge to exercise the on-demand fan at switch on would make sense , but not via increasing signal as seemingly thermal monitoring. Will check the minor rails first and then see if the high-power sections of the G PAs function, but at the moment I see no common section in the PA , between ch1 and ch2 other than power rails, that could cause that, later in actual use. Very unlikely matching components would both fail in ch1 and ch2 PA at the same time

"Gareth Magennis" wrote in news:qKvRy.1223993$ snipped-for-privacy@fx42.am:

However, Peavey service in the U.S. are very helpful with requests for service manuals, and help and advice with obscure problems.

Arfa

To be fair, that is my experience too so far.

One thing they were unable to help with though: I had 2 Peavey Pro 15 cabinets with blown HF diaphragms from different customers. (one just brought the driver/horn)

Now Peavey no longer supply replacement diaphragms for this driver, but now use a different driver and diaphragm altogether. (Mark 2 cab presumably) I bought 2 of these from Barnes and Mullins UK, after being told by Peavey this is the replacement, to find they were much bigger and heavier than the original, and do not fit in the cabinets.

I checked again with Peavey in case I had been supplied the wrong part, but in fact this is the part they think is a replacement.

Gareth.

Somewhere along the way this amp has acquired 2 printed pages of the G class PA, presumably someone accessed from Peavey as I cannot find it out in wwwland for a clearer image, useable images but should have been printed out as 4x A4 as some fine details is lost . pages titled Mixer amp 600 watts A, and internal doc number 99099390

Via chinese whispers I had got the diagnosis of a problem with the "forward processor" whatever that meant. Going by the ribbon damage to the digital board, perhaps it means problem with the Feedback Ferret (TM) falsely detecting feedback and inserting attenuation. I wonder if its possible to bypass/defeat that, if proves to be the problem

the full schematics including the G-Class PA and digital board is on

Still cold exploration. 3 bad ESR SMD 10Uf 16V caps, marked

on the digital board, one each on the Vcom pin of the ferret codec and the FX codec and another elsewhere, so could be injecting HF into the codecs. All other such caps ESR good Anyway hot testing next with Tx,Prea,PA spread-eagled across the bench.

Disconnecting digital board ribbon disables the amp. Audio input to the digital board is constant and the output has the drop of level on it, then on to PA Owner only has the 696 user manual, f for ferret presumably. On the back of the amp it says press ferret button for 6 seconds to disable it. This it does, bringing level right up, beyond even switch on level. So if this is level 1 on a speaker, then at switch on goes to 1/2 that level and soon drops to 1/10 of it. Press for 6 seconds and comes up to level 1. So presumably HF injection is triggering attenuation, so I'll replace all 3 10uF caps and see what happens

Got back to this digital problem. The third failed 10uF is on the "once-reset" / normal switch Q501/502 cct, on reset. Looks as though a failure of the cap could be interpreted as reset associated with loading new serial data via pcb pads and sprung probes ,which never arrived, well beyond anything I'd play with. There is an associated set of 3 pads for BOOT1 operation, I don't suppose anyone would know how to reset to normal mode. I think I'll leave as is, if it ain't actually broke, then don't poke. It should default to "performance" mode at switch on , but defaults each time to set up mode, for nullifying any feedback spot frequencies, the Ferret (TM). Normally you would press the mode button for 3 seconds to set it in this mode, then 6 seconds to go to performance. I think they'll have to press that button 6 seconds each time of use, although same equipment and venue each time.

eventually found the user manual , for this ferret thing