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New to Me Yamaha A-1000 - Heat Issue and Sound Cuts

JonLewis said:
I'm pretty confused, I can't find them in stock any where in metal film or the order amount is 1000+ units.

A thread on another A-1000 suggested a different value as replacement in metal film. Yamaha A-1000 in protection - Troubleshooting help

o_O
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https://www.mouser.com/c/passive-components/resistors/film-resistors/metal-film-resistors-through-hole/?power rating=500 mW (1/2 W)&resistance=27 kOhms&tolerance=1 %

Metal film, 1%, 1/2 watt. I didn't filter for size, but you can do it.

But the best advice is to go with Avionic's recommendation.
 
Looks like the recommended replacements are either 1/4 watt or 1/2 watt, and either metal film or carbon film, depending upon which of his recommendations you choose.
 
spark1 said:
Looks like the recommended replacements are either 1/4 watt or 1/2 watt, and either metal film or carbon film, depending upon which of his recommendations you choose.
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This app is just a voltage divider for the +/- 22 vdc supply voltage. OEM resistors are carbon film .250 watt . So no real advantage to using metal film.. They are not purposed for a " fusible " resistor. So upping the wattage is not going to be and issue.. So it don't really matter which film resistor you put in there. As long as its 27 KΩ @ 5% or less.
 
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Need some better DBT understanding.

I wired my new DBT per a video that included a meter test of the connections, so I should be good.

Without the DBT, the A-1000 powers and the relay clicks after 4 seconds. Has source.

Amp connected to the DBT with a 60W bulb it powers and dims the bulb a bit, no relay click, and no source.

Thoughts?
 
Soundscape said:
By the looks of that voltage divider & the heat it saw. I would use 1/2 watt resistors.


I'd use a bigger bulb. I use 150 watt incandescent on amps. 100 watt might be OK.
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Thanks!

I was just gonna post it needs more cranking power from the bulb watts. Amp relay did not click but my brain relay did.
 
Soundscape said:
By the looks of that voltage divider & the heat it saw. I would use 1/2 watt resistors.
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Voltage divider is 10 each 27KΩ in parallel for a total resistance & wattage of 2.7KΩ @ 2.5 watt for each 22v rail. Chances are there are other issues down stream if those resistors are drawing more current.
 
spark1 said:
That amp is likely to have some heavy dollops of glue around the larger capacitors (not the big filter caps), and "overflowing" onto peripheral components. This glue becomes corrosive over time, and potentially conductive. Glue needs to be removed, and any affected components replaced (those with glue on pins/legs).

The resoldering advice above is also dead-on. The A1000 is a very nice integrated amp, but they do run hot (and even hotter with the Class A switch activated).
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Hi John,
I would unplug the amp and do what this member said first thing. It's brown crap stashed under larger sized caps. Don't recommend using class A function until it's fixed. Have fun. It's rewarding when you're done.:thumbsup:
 
avionic said:
Voltage divider is 10 each 27KΩ in parallel for a total resistance & wattage of 2.7KΩ @ 2.5 watt for each 22v rail. Chances are there are other issues down stream if those resistors are drawing more current.
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Reminds me of the fan control resistors in my old cars. Old & toasty
 
Soundscape said:
Hi John,
I would unplug the amp and do what this member said first thing. It's brown crap stashed under larger sized caps. Don't recommend using class A function until it's fixed. Have fun. It's rewarding when you're done.:thumbsup:
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Yes, I was trying to get the DBT squared away and a quick test with it.

I also got a ESR meter to take an initial check of the caps.

Looking to get an iron next. Am I better off just re-flowing the cold solder issues, or remove the old solder completely?

I'll get some kits for my learn curve and beat those up.
 
JonLewis said:
Yes, I was trying to get the DBT squared away and a quick test with it.

I also got a ESR meter to take an initial check of the caps.

Looking to get an iron next. Am I better off just re-flowing the cold solder issues, or remove the old solder completely?

I'll get some kits for my learn curve and beat those up.
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Reflowing over the old solder joints without making blobs should be fine, no need to remove old solder. Remember, the less heat applied (directly or indirectly) to solder pads the better, at some point they might come off the board and create other issues.
 
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JonLewis said:
Yes, I was trying to get the DBT squared away and a quick test with it.

I also got a ESR meter to take an initial check of the caps.

Looking to get an iron next. Am I better off just re-flowing the cold solder issues, or remove the old solder completely?

I'll get some kits for my learn curve and beat those up.
Click to expand...
JonLewis said:
Looking to get an iron next. Am I better off just re-flowing the cold solder issues, or remove the old solder completely?
Click to expand...
I would just re-flow the old while adding a little new solder. Recommend an iron with adjustable temperature. It's worth the extra $. Heat the component leads, not the board. 2-3 seconds tops. Too much heat & the little circular solder lands peel up, crack, break etc. I use 450-475 degrees F on board components. Then crank up temp on heat sink mounted parts, copper bars, etc.
DBT. With 100-150 watt bulb, it should brighten up for 2-3 seconds upon power up and then dim way down to little more than an orange filament glow. Less than a candle. That means there's no shorts. Bright light means trouble (short) & turn power off now.The DBT starves the amp of current.
I like chiming in on fundamentals but I'll leave the technical particulars to the other fellas here posting. Compared to most of them... I just got out of diapers.
 
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