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January 25, 2022, 05:29:49 PM

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71
Amplifier Discussion / Re: Yamaha G100
« Last post by semjmiyta on January 05, 2022, 01:40:49 AM »
Thank you very much for the info. And correct no fix loop and a high low input and a preset volume which I’m guessing is the channel switch I’m familiar with the boards you’re mentioning as I’ve had to repair a really word diode attached to the big heat sink and you were right again about the jacks (the speaker out jacks are these huge screw type old switchcraft type that I did have to clean
Would any transistors maybe too old now cause it to be lack luster?
I’ll check those pins you mentioned for sure thanks again
72
Amplifier Discussion / Re: Heathkit TA-16 Tripping Breaker
« Last post by ilyaa on January 05, 2022, 01:35:16 AM »
i tried a 1A slo blow - will try 2A slow blow and see what happens!

reason i thought 1A slow blow would be okay as a first go was that my ammeter was showing 0.5 amp when the breaker was tripping - was showing 0.5A when the 1A slow blow cooked.

i might try switching the breakers first and then try a 2A slow blow fuse depending on the results -
73
Amplifier Discussion / Re: Heathkit TA-16 Tripping Breaker
« Last post by Enzo on January 05, 2022, 12:07:50 AM »
You replaced a 2 amp breaker with a 1 amp fuse?  Well that doesn't tell me much.  Please tell me it was at least not a fast blow 1A.

Actually weak breaker was my first thought too.  You are throwing parts at it based on possible current surges.  But how about if the breaker is weak, then it doesn't care about peaks.

A fuse isn't a bad idea, but at least use a 2A SLOW or even a 2.5A.
74
Amplifier Discussion / Re: Yamaha G100
« Last post by Enzo on January 04, 2022, 11:59:30 PM »
My first reaction would always be check the FX loop jacks.  But I don't think you have them, do you?

I love these amps.  The power amp is on the heat sink assembly hanging from the chassis.  A couple large bolts and it unplugs from the interior board by a 6-pin connector.   Just my guts hunch, but pull that assembly off and check the pins on the connector.  Any cracks on the pin solder?  or just simply resolder them anyway.  Likewise, inside, I think it is the power supply board has the mates for the six pins, resolder those.

It could be anything, of course, but caps don't come and go.  You have a symptom that does come and go.  I'd be looking for a failing connection.  A weak solder joint or a jack with poor contacts.

You have two channels, do BOTH channels act the SAME way?

And just a thought, you have hi and low jacks for each channel.  You likely use just the HI.  Plug into the LOW jack on a channel.  Does that sound like the "problem" condition?  If the cutout contacts in the LOW jack are dirty, the amp will stay in the low condition even using the HI jack.
75
Amplifier Discussion / Re: Heathkit TA-16 Tripping Breaker
« Last post by ilyaa on January 04, 2022, 08:49:02 PM »
i did try that by replacing the breaker with a 1 amp fuse. that blew, too

and its the second breaker, on the secondary side of the PT, that is being tripped.
76
Amplifier Discussion / Re: Heathkit TA-16 Tripping Breaker
« Last post by g1 on January 04, 2022, 08:32:15 PM »
Is it the same breaker tripping every time?
Does your meter have a peak hold function or anything like that?  It may be that the meter is just too slow.
If it's not too involved, you could swap the breakers around and see if the problem follows one particular breaker.  It's not common, but they do get weak sometimes.
77
Amplifier Discussion / Heathkit TA-16 Tripping Breaker
« Last post by ilyaa on January 04, 2022, 08:13:22 PM »
hey happy new year everyone!

wouldnt be posting if i wasnt stumped....

got a Heathkit combo on the bench. kind of a weird one, but sounds rad! works alright, until you turn it up. after 3-4 seconds of full power, it trips the breaker (this amp has two 2 amp breakers rather than fuses).

i hooked an ammeter to it and its only drawing 0.5 amps or so right before it trips the breaker, so the high current draw must happen fairly quickly.

here is what ive tried so far:

replaced c104. thats the oldest electrolytic in there - the other ones are fairly new. replaced c34, c21, c17, c22. no diff.
outputs looked fine but i replaced em anyway (Q10 and Q9).

before i start swapping the rest of the transistors out, wanted to see if any of you brilliant minds had some thoughts as to what might be happening. the strangest thing is it works totally fine and if i reset the breaker it comes right back on, no problem. its only when it reaches near full power that something seemingly starts to cascade and draw too much current. the output stage is a bit tricky for my brain (mixed germanium and silicon, for starters...) - please enlighten me!!

78
Amplifier Discussion / Yamaha G100
« Last post by semjmiyta on January 04, 2022, 06:38:33 PM »
I have a general consensus type question (kinda). I am playing through a Yamaha G100 just the head no combo all my Uber high high gain I get from pedals, Lately when it’s time to jam it isn’t the same .It’s not tube so no warming up silicone trannies. So I'm thinking my same settings day to day won’t change for a few weeks but some of the screaming sustain I’d get would be there one or 2 days not there the next day etc. No change of strings pots nothing . So.
Recap?
Seems the obvious choice
Seeing I love high gain all through pedals it’d be a win win No?
Cleaner amp. Thoughts and suggestions anybody?
 I have the series one G100 series 1 running through an old Altec Lansing 15” and when the Yamaha is kicking it screams I love it  but when it’s not can’t seem to dial in anything close just figured I’d throw it out there before I go for it
79
The Newcomer's Forum / Re: Danelectro Nifty Fifty distortion and hiss
« Last post by Jazz P Bass on January 04, 2022, 11:46:00 AM »
At 15 watts output, being a solid state amplifier, I can't imagine that it would draw more than 1 amp at 110Vac.
At 220 Vac it would be half.
80
The Newcomer's Forum / Re: Danelectro Nifty Fifty distortion and hiss
« Last post by cabell64 on January 04, 2022, 07:29:45 AM »
I am SO happy to see a current discussion (no pun intended) about this amp.

I just moved to Europe, and powering my amps has become an issue. I have a big step-down transformer coming, but, I would like to know.... What is the current draw for this amplifier in watts????  I'm having a hard time wrapping my head around how many watts it needs as to not over-tax my other step down transformers?
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