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lost one channel on an old Onkyo amplifier

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Guest

Tue Aug 11, 2015 2:47 am   



On Monday, August 10, 2015 at 6:47:54 PM UTC-4, jurb...@gmail.com wrote:
Quote:
"P.S. I have NOS STKs available if the ones listed up thread are accurate. "

Do you happen to have an STK0100 II and if so, how much ? I am already fitting one into a Fisher CA-800 that used to have 0080s in it. The one I got I know is NOS. It might be nice to do both at the same time because I have to do some things to the heatsink because the 0100 is bigger.


I have (2) STK0080II and (2) STK0100II available.

Dan

Tim R
Guest

Tue Aug 11, 2015 5:21 am   



On Monday, August 10, 2015 at 3:17:50 PM UTC-4, pf...@aol.com wrote:

Quote:
On the other hand, fuses do get weaker with age and strain. It may well be that one or another of them is blown. DO NOT rely on visual inspection to determine if a fuse is good or not. A fuse that fails from age typically does so at the solder point, and that would be invisible. Check with a VOM, or simply install new fuses. If one is visibly blown, however, try to look for a cause before plugging in a new fuse.


I am reasonably smart but capable of horrendous brain cramps for no apparent reason. This got suddenly much worse after my 60th birthday and I am somewhat concerned.

However, I am not yet stupid enough not to check the fuses. They are fine.

Okay, I admit, I did not know there were speaker fuses on an amp, I've never blown one. But when I turned it around, I saw the panel that said Speaker Fuses and I opened it and checked them with a VOM. I used my cheap Radio Shack digital, but when in doubt I always reach for the Simpson, old reliable 260D.

and then

I got to thinking.

I was pretty sure this was the amp that didn't have a balance control. I remember how much grief that caused me when I really needed one.

So, that's the one thing I didn't check.

What if I'd remembered wrong? What if one of the kids moved the PC and bumped the balance knob?

CRAPCRAPCRAPCRAPCRAP!!!!!!!!

The balance knob was all the way to one side and when moved back to center, the Onkyo is fixed.

When I had the Onkyo off the table, I'd replaced it with a Pioneer home theater unit. I am so glad to get rid of that one, it really sucked compared to the Onkyo. I am not really an audiophile - I can tell the difference between good and bad styluses, good and bad speakers, but never was able to tell much about the amplifier. But the Onkyo is head and shoulders above the Pioneer.

Rheilly Phoull
Guest

Tue Aug 11, 2015 7:30 am   



"Tim R" wrote in message
news:bac45eb6-f681-4ec4-b774-274e88730824_at_googlegroups.com...

On Monday, August 10, 2015 at 3:17:50 PM UTC-4, pf...@aol.com wrote:

Quote:
On the other hand, fuses do get weaker with age and strain. It may well be
that one or another of them is blown. DO NOT rely on visual inspection to
determine if a fuse is good or not. A fuse that fails from age typically
does so at the solder point, and that would be invisible. Check with a
VOM, or simply install new fuses. If one is visibly blown, however, try to
look for a cause before plugging in a new fuse.


I am reasonably smart but capable of horrendous brain cramps for no apparent
reason. This got suddenly much worse after my 60th birthday and I am
somewhat concerned.

However, I am not yet stupid enough not to check the fuses. They are fine.

Okay, I admit, I did not know there were speaker fuses on an amp, I've never
blown one. But when I turned it around, I saw the panel that said Speaker
Fuses and I opened it and checked them with a VOM. I used my cheap Radio
Shack digital, but when in doubt I always reach for the Simpson, old
reliable 260D.

and then

I got to thinking.

I was pretty sure this was the amp that didn't have a balance control. I
remember how much grief that caused me when I really needed one.

So, that's the one thing I didn't check.

What if I'd remembered wrong? What if one of the kids moved the PC and
bumped the balance knob?

CRAPCRAPCRAPCRAPCRAP!!!!!!!!

The balance knob was all the way to one side and when moved back to center,
the Onkyo is fixed.

When I had the Onkyo off the table, I'd replaced it with a Pioneer home
theater unit. I am so glad to get rid of that one, it really sucked
compared to the Onkyo. I am not really an audiophile - I can tell the
difference between good and bad styluses, good and bad speakers, but never
was able to tell much about the amplifier. But the Onkyo is head and
shoulders above the Pioneer.


Well mate you would not be alone, there wouldn’t be many casual repairers
that haven't done similar !!

Dave Platt
Guest

Tue Aug 11, 2015 11:57 pm   



In article <bac45eb6-f681-4ec4-b774-274e88730824_at_googlegroups.com>,
Tim R <timothy42b_at_aol.com> wrote:

Quote:
What if I'd remembered wrong? What if one of the kids moved the PC and bumped the balance knob?

CRAPCRAPCRAPCRAPCRAP!!!!!!!!

The balance knob was all the way to one side and when moved back to center, the Onkyo is fixed.


There was much rejoicing!

I recently had a bad scare with the FM service monitor that I had
dragged down to our city's ARES/RACES ham shack. I'd been asked to
run a full check on all of the UHF/VHF radios, and the service monitor
wasn't "seeing" any signal on any frequency. When I switched it to
"generate" mode, there was no output at all.

I thought the frequency synthesizer circuit had died, and resigned
myself to hauling it home for a full investigation and repair.

Just as I was finishing the box-it-up process, I thought "Hmmm... one
thing I ought to double-check..." and I turned it around and looked at
the back panel.

Sure enough... the tiny little time-base switch was set to
"external". The last time I had used it, I'd been feeding it a 10 MHz
reference signal from my rubidium oscillator, and had forgotten to
switch it back to its internal time-base when I was done.

Threw the switch to "internal", checked it again, and the synthesizer
was working fine.

I gave myself a slap on the wrist for not resetting it to normal
operation after the previous usage... and breathed a sigh of relief
that I'd discovered the error before I went all the way home with it.


Guest

Wed Aug 12, 2015 12:04 am   



>"The balance knob was all the way to one side and when moved back to center, >the Onkyo is fixed. "

I've seen worse. That just happened to me and I am a pro. I had a similar unit, in fact an Onkyo TX-2500 which is a bit older, has no digital/quartz lock thingie in it. It DID have a blown speaker fuse, blown by fatigue actually. I put that in and I got one channel. Oh shit. So I take the bottom off and stat checking. The silent channel has no input to the power amp board, I trace it back to the tone board and sure enough it is losing it there. I get all the way to the output end of it and I see the transistors are amplifying just fine, but is dropped across a resistor. OK, open resistor, right ? Nope, checks fine. Must be a short circuit.

Guess how balance controls work. They short out the audio ! (that is how the get max gain in the center position, except a few which use a dual pot) Open a window ! BRAIN FART !

>"I am not really an audiophile - I can tell the difference between good and >bad styluses, good and bad speakers, but never was able to tell much about the >amplifier. But the Onkyo is head and shoulders above the Pioneer. "

I suspect you of being a closet audiophile. Or maybe you are in denial. lol

Really, it doesn't take a ten grand system. It doesn't have to be 30 years old. You might want to browse around audiokarma. Some interesting reading not only about how stuff sounds different even with the same power and specs, but WHY. If you're inclined you'll probably find some interesting threads there. Lately there have been discussions about damping factor and what KIND of distortion different amps or other equipment has and how well you can hear this or that.


Guest

Wed Aug 12, 2015 12:07 am   



On Monday, August 10, 2015 at 7:47:12 PM UTC-5, dansabr...@yahoo.com wrote:
Quote:
On Monday, August 10, 2015 at 6:47:54 PM UTC-4, jurb...@gmail.com wrote:
"P.S. I have NOS STKs available if the ones listed up thread are accurate. "

Do you happen to have an STK0100 II and if so, how much ? I am already fitting one into a Fisher CA-800 that used to have 0080s in it. The one I got I know is NOS. It might be nice to do both at the same time because I have to do some things to the heatsink because the 0100 is bigger.

I have (2) STK0080II and (2) STK0100II available.

Dan


How much and how far are you from Cleveland, Ohio ? I'll have to see if the guy ants to spend the bucks as well. Hopefully you don't wnat so much for them we have to put the money in escrow. I have had good luck with people on Usenet so I wouldn't mind trusting and just sending you a postal money order. (they are not forged because there is an 800 number you can call to verify them) I don't have a Paypal account but I know someone who does if you have to be paid that way.


Guest

Wed Aug 12, 2015 12:20 am   



>"There was much rejoicing! "

My cohort and I sometimes buy used scopes from this surplus place on the east side. (I know most people don't mention that but us old west siders do around here)

Got a couple of pretty good deals, not extremely great scopes but usable for audio and a few other tings. Anyway, then people don't really know scopes ad we found that some of them, THEY don't know how to get a trace on them. Like setting them to auto trigger, or free run if it has it. Picked up a nifty Tek 422 with the battery option. I intend to replace the batteries with more modern ones but I am sure I am going to have to build the charging circuit. I might see about an of the shelf solution or possibly get the circuitry from an old laptop. I would hav to probably cut part of the motherboard or something, if that is even possible, and then most likely regulate the 19 volts down to 12, pretty sure it is 12.

And we got a Tek 7834 that used to cost more than a house for like $24. That tone however has a slight HV regulation problem which I will eventually get to. the main worry about that is that it is a big HV divider resistor. but then modification is my middle name for a reason. There is almost always a ay, andf the other surplus place (slightly farther, they are on the west side of the next place)has kagillions of old resistors, probably of every value ever made. And I mean 100.1 meg, 100.2 meg, you know. OK, I am exaggerating, but not that much.


Guest

Wed Aug 12, 2015 12:24 am   



Quote:
"Now if there had been a sensible warning light on the front panel you
might have noticed earlier... "


Things like that irk me. YEARS worth of Tek stuff with no power light. Some have a little window that opens to reveal a light colored piece of plastic.. Ridiculous. Same with these older Wavetek generators. Muy biddy has a 103 and I have a 111, they also lack a power light.

Can't even tell if the thing is plugged in, and that is important sometimes, depending on how your bench is set up. If you are out in the field it is even worse.

Don't pick on our old equipment, at least it doesn't run Windows !

MJC
Guest

Wed Aug 12, 2015 12:45 am   



In article <3mpp9c-ath.ln1_at_coop.radagast.org>, dplatt_at_coop.radagast.org
says...
Quote:
I gave myself a slap on the wrist for not resetting it to normal
operation after the previous usage... and breathed a sigh of relief
that I'd discovered the error before I went all the way home with it.


Now if there had been a sensible warning light on the front panel you
might have noticed earlier...

Mike.


Guest

Thu Apr 02, 2020 8:45 pm   



Try the fuse. I had same problem on a 80s TX 2500. It was one of the fuses. Replace both.

John-Del
Guest

Thu Apr 02, 2020 8:45 pm   



On Thursday, April 2, 2020 at 3:14:58 PM UTC-4, mcurr...@gmail.com wrote:
> Try the fuse. I had same problem on a 80s TX 2500. It was one of the fuses. Replace both.

Almost 5 years ago. I suspect he either repaired it, had it repaired, or scrapped it by now.

John-Del
Guest

Thu Apr 02, 2020 8:45 pm   



On Thursday, April 2, 2020 at 3:14:58 PM UTC-4, mcurr...@gmail.com wrote:
> Try the fuse. I had same problem on a 80s TX 2500. It was one of the fuses. Replace both.

That was 5 years ago. Also, he said it was just the balance control mistakenly rolled over to one side.


Guest

Mon Apr 06, 2020 5:45 pm   



John-Del wrote:

Quote:
That was 5 years ago. Also, he said it was just the
balance control mistakenly rolled over to one side.


________
If so, then the only issue with this amplifier was lack of basic trouble-shooting.

Tim R
Guest

Tue Apr 07, 2020 4:45 pm   



On Monday, April 6, 2020 at 12:41:42 PM UTC-4, thekma...@gmail.com wrote:
Quote:
John-Del wrote:

That was 5 years ago. Also, he said it was just the
balance control mistakenly rolled over to one side.

________
If so, then the only issue with this amplifier was lack of basic trouble-shooting.


I'm still here, the Onkyo still works, at least as of last night.

Annoyingly, now moving the volume control causes some fuzz and one speaker drops out, but usually comes back with a few rapid twists. But the sound quality is good.

pfjw@aol.com
Guest

Tue Apr 07, 2020 5:45 pm   



On Tuesday, April 7, 2020 at 10:52:42 AM UTC-4, Tim R wrote:

> Annoyingly, now moving the volume control causes some fuzz and one speaker drops out, but usually comes back with a few rapid twists. But the sound quality is good.

Lack of basic troubleshooting, and, apparently, basic maintenance.

Clean the controls, starting with the VC, then all other pots and switches. Should be good for another 5 years after that!

Peter Wieck
Melrose Park, PA

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