Peavey Valve King 212

[N_Cook]

only 6 months old , barged into a door apparently but owner cagey. No
mention of what happened when powered up. 10 watt resistor overheated to
burn up cabling and black "candy floss" everwhere inside.
Will be a while before I can get any power onto it, schema on elektrotanya.
But anyone know the DC ohmages of the transformers ? These readings look ok
, genericaly speaking
o/p primary 29.8/24.6 R

mains primary for 240V 4.4R
sec
heater 0.4R
HT 14.2R
other DC 74.4R

 

[N_Cook]

You would think that a 10W resistor marked on the schematic as a safety
device would mean that any wiring would be loomed away from it, not laying
along its length. Another safety issue with these amps, I was trying to see
where the chunky HT wire to the output amp was, but nothing obvious. It is
in the grey ribbon umbilical , >500V rating on that stuff? I doubt it. 6
months old , no warning signs of crap solder used, no PbF / RoHS /N or even
the CE mark for this , for export, 240V structured amp, just a wheelie bin
with an X over it.

 

[Cydrome Leader]

You would think that a 10W resistor marked on the schematic as a safety
device would mean that any wiring would be loomed away from it, not laying
along its length. Another safety issue with these amps, I was trying to see
where the chunky HT wire to the output amp was, but nothing obvious. It is
in the grey ribbon umbilical , >500V rating on that stuff? I doubt it. 6
months old , no warning signs of crap solder used, no PbF / RoHS /N or even
the CE mark for this , for export, 240V structured amp, just a wheelie bin
with an X over it.

speaking of stupid symbols, what's the circle with an arrow possibly
indicating some sort of rotation and a number "10" inside mean?

 

[N_Cook]

speaking of stupid symbols, what's the circle with an arrow possibly
indicating some sort of rotation and a number "10" inside mean?

If you are talking of plastics moulding mark then the "hour" of the pointer
is the month of the castings in 2010

 

[Geo]

speaking of stupid symbols, what's the circle with an arrow possibly
indicating some sort of rotation and a number "10" inside mean?

Probably just one of the old amps where the volume does not go up to
11.

 

[N_Cook]

Anyone know how to read the plastic mouldings marks where it is 2 or 3
simple bars, not arrows, in 2 or 3 circles. It seems the bar is never
central but pushed to one side , is that the arrow direction? Then if 2
circles first "2 o'clock", say, is 2002 and second "3 o'clock " say, is
march. Then 3 dials is year/ month/ week ?

 

[N_Cook]

Saw one of these a while ago and had to hard wire the ribbon cable between
pre-amp/power amp boards as it had arced/burnt the connectors.

One thing I particularly remember is the OPT input feed is connected via a
plug and socket to the output PCB and, unlike most Peavey units, it is
possible to connect this the wrong way round. This will result in all sorts
of weird feedback/oscillations, particularly when playing with the
"resonance" pot on the back panel.

This amp cost me a lot of time and frustration.



Gareth.

At least the OPT wires are proper 500V rating. I ' ve now marked that
connector JIC.
I imagine your ribbon problem was initially the euro-crap solder inside.
I've pared off the HT wire and spiral wrapped some sleeving around it. The
wiring to the standby switch will go the other side of the main caps not
over the replaced 400R 10W dropper that had exploded to 3 bits in the
conflagration.

 

[Jamie]

I think it was actually the heater circuit that burnt the connector
contacts, though I'm not 100% sure of that.
I've seen this same burning on other equipment too, usually the high
current PSU connectors, (Molex?).


Gareth.

A good cleaning and use of antioxidant electrical compound on the
connections usually helps there.

Jamie

 

[N_Cook]

Hard wiring to bypass a poor design / poor choice of connector works a lot
better IMHO.



Gareth.

Over time sprung connections loose their spring. Sorted out someone's
favourite amp last week, a number of crimp spade connectors inside, cut off
and soldered in , should be fine for another 20 years

 

[N_Cook]

I think it was actually the heater circuit that burnt the connector
contacts, though I'm not 100% sure of that.
I've seen this same burning on other equipment too, usually the high current
PSU connectors, (Molex?).


Gareth.

I was wondering about the current rating through the ribbon for the op
heaters but they are daisy-chained and then awkwardly connected to the pre
heaters, confusingly.
As this is only 6 months old perhaps a stock fault previously , the ribbon
here is soldered either end

 

[N_Cook]

I seem to remember something odd about the heater circuit - is there not
some kind of series/parallel thing going on?
I seem to recall you can't pull one or more of the pre-amp tubes to leave
just the phase splitter and o/p valves working.


It's possible I'm confusing this with another amp, but you have just rung a
bell in my head.



Gareth.

yes very odd , at first sight all valve heaters pa and prea, .9A and .3A are
daisy-chained in series but there is another ps tap off point labelled 6V or
6V1 for the high current tubes

 

[N_Cook]

Its confused because V3 splitter driver is physically on the op pcb, but all
3x .3 amp heater valves (6.3V setting) are in parallel for .9 amp total at
node ( 6V or 6V1) and then in series with the 4 output valves, each at .9
amp so in effect current-wise 5x .9 amp in series and 5 x 6.3V supply

 

[N_Cook]

Maybe that's so they can use Mickey Mouse connectors/PCB traces at 1 amp
capacity rather than have to hand wire proper heavy duty wires.
Whatever, it doesn't seem to work very well.

Makes a bit more sense now though, cheers.


Gareth.

So anyone live swapping V1,2 or3 will get too much power to the heaters on
the remainder . Or with heater failure in one triode may lead to a cascade
of failures assuming the mate of the first failed one would be similarly
disstressed.

 

[Cydrome Leader]

speaking of stupid symbols, what's the circle with an arrow possibly
indicating some sort of rotation and a number "10" inside mean?

It's not a plastic type designator, I've seen it stamped on metal stuff
too.