So I got this Silvertone integrated amp. I kind of like it as the styling is
pretty retro but it is sort of beat up. Not exactly resalable looking if I
was to decide to sell and move on to bigger or better things.

Well when I got it the guy plugged it in to demo it for me and it hummed
pretty badly so he just gave it to me for my trouble coming out to see it.
He told me that it was most likely the PS caps had dried out and to replace
them and it should be good again. I brought it home and replaced all the
large electrolytic caps I could find and sure enough the hum went away.
Right off I noticed that one channel seemed to be a bit louder than the
other but I adjusted the balance and listened on. After a bit I noticed that
one of the channels seemed to sound garbled so I went and looked at the amp
and the tubes on that channel were glowing red so I shut it down. Not just
the normal glow but the whole metal mechanism inside the tube was cherry
red. I have poked around with my DMM to see if there was something different
I could find between the normal running channel and the hot one but I am not
finding anything and I don't really know enough to try to troubleshoot it
any further.

Anybody have any fairly strait forward suggestions about what to look for
and where? I surely wouldn't mind fixing the amp and using it as it is. It's
a Silvertone model # 2029 by the way. 2 x 10 watts. 2 x 7199, 1 x 12AX7, and
4x 6BQ5.

On the other hand I am looking for a kit or project to build so I can learn
a little more about this hobby. I am looking at this amp and know I like the
basic parts of it and would like to have an amp like it but it doesn't have
to be this amp in particular. I am of course wondering if I could just take
the basic pieces of this amp and make something simpler and more stream
lined out of it. Get new sockets and just reuse the iron and some of the
switches and stuff. Things like the input selector and the volume. I really
don't need the tone controls and balance. Anybody got some idea what parts I
have and know of a good project to use them in?

Lots of questions,
Bryan
Durham, Oregon.

Well when I got it the guy plugged it in to demo it for me and it hummed
pretty badly so he just gave it to me for my trouble coming out to see it.
He told me that it was most likely the PS caps had dried out and to replace
them and it should be good again. I brought it home and replaced all the
large electrolytic caps I could find and sure enough the hum went away.
Right off I noticed that one channel seemed to be a bit louder than the
other but I adjusted the balance and listened on. After a bit I noticed that
one of the channels seemed to sound garbled so I went and looked at the amp
and the tubes on that channel were glowing red so I shut it down. Not just
the normal glow but the whole metal mechanism inside the tube was cherry
red. I have poked around with my DMM to see if there was something different
I could find between the normal running channel and the hot one but I am not
finding anything and I don't really know enough to try to troubleshoot it
any further.

Anybody have any fairly strait forward suggestions about what to look for
and where? I surely wouldn't mind fixing the amp and using it as it is. It's
a Silvertone model # 2029 by the way. 2 x 10 watts. 2 x 7199, 1 x 12AX7, and
4x 6BQ5.


Given the price range, and power range of the amplifier, it's most likely
cathode bias. Something is biasing the faulty channel way too hot, and it's
either a result of leaky coupling capacitors, or, a shorted electrolytic cathode
bypass capacitor.

Replace the coupling capacitors between the 6BQ5's, and the 7199's. They will be
a pair of identical capacitors, probably in the 0.1 uF 400V range. Buy something
close, but it dosen't have to be identical. A higher voltage rating is not a
problem. Also, relace any electrolytic capacitors between the cathodes of the
6BQ5's, and ground. At this point it would be a good idea to also replace the
pair of 6BQ5's which was glowing cherry red. Use a pair of Sovtek EL84 tubes
from a guitar shop - they shouldn't be expensive (EL84 is the European
designation for 6BQ5). This should make your amplifier work, and cost is
minimal. Once you get to this stage, it would be a good idea to clean all the
controls in the amplifier with contact cleaner from radio shack, and listen to
it long enough to see if it's worth keeping or not... try a variety of music,
and some fairly sensitive speakers.

Oh, and if you're not sure what pin is what... check out
www.triodeelectronics.com, go to the tube data page, find 6BQ5, and you will get
the pinout of the tube,

Hope this helps

Max

P.S. Do not attempt to operate the amplifier until you repair it, as the fault
it has could damage the amplifier if you leave it on for any period of time.

P.P.S. Once you get the faulty channel working, it would be prudent to replace
all of the other electrolytic and paper capacitors in the amplifier.

This seems to have done it I think. After you saying the coupling caps were
between the 7199 and the EL84 I was able to find them. Someone had made that
suggestion before but they said output in there somewhere and I didn't see
any caps going into or out of the OPTs. I looked in the right place now and
found two caps there were .047 mfd @ 400VDC. I replaced them with .04 mfd
orange drops. I am still not sure that the amp is 100% as in the process of
hooking up the speaker wires I chipped the tip off one of my 7199s. I did
put the one working 7199 into the suspect channel and have had it running
for awhile now and no unusual glowing so I think it's fixed.

Oh the trial and tribulations. While I had the amp apart replacing those
caps I screwed the circuit board back down and cracked it and broke two or
three traces. there are shields around the 7199s and one of the shields had
jammed against the chassis so when I tightened the screw it bent the board
and "snap". I jumpered around the broken traces with bits of the leads I cut
off the orange drops and a piece of copper wire. It seem to work fine.

I'll try and find a pair of 7199s and replace them as a pair and report back
my findings. If it seems like it's working right I'll find matching EL84s
also.

WooHoo,
Bryan
Durham, Oregon.
"Max Holubitsky" wrote in message
...
Well when I got it the guy plugged it in to demo it for me and it hummed
pretty badly so he just gave it to me for my trouble coming out to see
it.
He told me that it was most likely the PS caps had dried out and to
replace
them and it should be good again. I brought it home and replaced all the
large electrolytic caps I could find and sure enough the hum went away.
Right off I noticed that one channel seemed to be a bit louder than the
other but I adjusted the balance and listened on. After a bit I noticed
that
one of the channels seemed to sound garbled so I went and looked at the
amp
and the tubes on that channel were glowing red so I shut it down. Not
just
the normal glow but the whole metal mechanism inside the tube was cherry
red. I have poked around with my DMM to see if there was something
different
I could find between the normal running channel and the hot one but I am
not
finding anything and I don't really know enough to try to troubleshoot
it
any further.

Anybody have any fairly strait forward suggestions about what to look
for
and where? I surely wouldn't mind fixing the amp and using it as it is.
It's
a Silvertone model # 2029 by the way. 2 x 10 watts. 2 x 7199, 1 x 12AX7,
and
4x 6BQ5.


Given the price range, and power range of the amplifier, it's most likely
cathode bias. Something is biasing the faulty channel way too hot, and
it's
either a result of leaky coupling capacitors, or, a shorted electrolytic
cathode
bypass capacitor.

Replace the coupling capacitors between the 6BQ5's, and the 7199's. They
will be
a pair of identical capacitors, probably in the 0.1 uF 400V range. Buy
something
close, but it dosen't have to be identical. A higher voltage rating is not
a
problem. Also, relace any electrolytic capacitors between the cathodes of
the
6BQ5's, and ground. At this point it would be a good idea to also replace
the
pair of 6BQ5's which was glowing cherry red. Use a pair of Sovtek EL84
tubes
from a guitar shop - they shouldn't be expensive (EL84 is the European
designation for 6BQ5). This should make your amplifier work, and cost is
minimal. Once you get to this stage, it would be a good idea to clean all
the
controls in the amplifier with contact cleaner from radio shack, and
listen to
it long enough to see if it's worth keeping or not... try a variety of
music,
and some fairly sensitive speakers.

Oh, and if you're not sure what pin is what... check out
www.triodeelectronics.com, go to the tube data page, find 6BQ5, and you
will get
the pinout of the tube,

Hope this helps

Max

P.S. Do not attempt to operate the amplifier until you repair it, as the
fault
it has could damage the amplifier if you leave it on for any period of
time.

P.P.S. Once you get the faulty channel working, it would be prudent to
replace
all of the other electrolytic and paper capacitors in the amplifier.