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Cleaning old smelly Combos

#61
I think most of what you're calling timer chips are analog op amps -- monolithic integrated operational amplifiers. A transconductance amp chip is also not a timer. What I don't understand is why one would hold forth so boldly and determinedly about something about which they obviously know so little. I may not know much, but I usually know enough to know what I don't know.
 
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#64
Tpi said:
I learned new information critical to the long term function of this device.

There are ten IC timer chips on that board. The full part number for the one I mentioned, of which there are eight, is "TI RC4558A". It's a "General Purpose Amplifier 2 Circuit Differential 8-PDIP" and vaguely speaking generates a reference voltage that the the incoming voltage is regulated to and sent out as. I'm probly a little off on that for the cursory glance I gave it. Good news here is they remain in wide production and are on ebay for under $1 to several $ each depending. Needing up to 8, a 10-pack is ~$10.

The remaining two chips are the same and a doozy if either goes. They list as "RCA519 70487478". This is to say it is not a 519, nor 7048 nor a 7478 chip, but an internal Peavey code for their select choice of what is a common chip, the CA3080 or CA3094. Those are both "8 pin Transconductance Amplifier 1 Circuit Push-Pull 8-MDIP". Apparently they take a voltage/signal error and use that offset to drive a relay or other controller option. Apparently the chips Peavey chose were highly select versions of the common, rendering the common runs useless. Apparently folks at the Peavey forums can't even determine what the actual function is in the circuit and the old timers are vague too. And apparently the best option given by old-timer techs is to scavenge parts from a dead unit and hope it's not the same chip that's dead.

So that apparently sucks.
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None of this is correct either, there are no timers or relay drivers (or relays) on that amp. Nothing even remotely close to that either.

If you present something as fact yet don’t understand even the most basic part of how it works works, how do you expect anyone to take you seriously (or be able to troubleshoot and repair a fault)?
 
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#65
I've gotta go thru and read all these new comments, but I'm glad yours is most recent.
agedhorse said:
If you present something as fact...
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Fact: Integrated circuits of this variety and era are generically, off-handedly and colloquially referred to as timer chips even if they be op amps and other not-timers.

Fact: Those chips are as stated unless the texas insruments and peavey forums and digikey and other links are lying to me simply to infuriate you. In such case, I congratulate such a grand conspiracy on its unquestionable success!

Fact: I strongly suspected your post Sorry terribly wrong was pure sarcasm.

Fact: You are under no obligation to read this thread.

Fact You are choosing to waste the precious moments that compose your life here in this thread.

Fact: Your sunshine warms and soothes the spirit. I hope you can now share it elsewhere with others.

You don't have to stay, but i don't understand why you're back. Throw me on your ignore list and go smile out the window at that little bird and squirrel playing in the tree. May your day be pleasant with happy colors and swirly dreams.
 
#67
Tpi said:
Fact: Integrated circuits of this variety and era are generically, off-handedly and colloquially referred to as timer chips even if they be op amps and other not-timers.
Fact: Those chips are as stated unless the texas insruments and peavey forums and digikey and other links are lying to me simply to infuriate you.
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:laugh: :roflmao: :thumbsup:

Please report back your success in restoring this valuable amp.
 
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#68
The winner was lysol disinfecting wipes on the cab with a hose down and sunlight for a few days.

On completion of cleaning, the cab will be given away to my local guitar shop or left in an alley to fend for itself.

Only the amp, cones and resonator are being retained for a new custom housing of approx. same size

This combo likely hauled alot of manure around over the years (still going apparently). So wood burned across its face somewhere will be christened its new name, "very ancient workhorse" to honor it's ~40 years of existence.

As to lesser matters, some folks likely call a dromedary a camel, porpoises dolphins and crocodiles alligators and still have the exactitude to be pedantic rivet counters. Lotta nonsense is all words are and create.
 
#69
In over 40 years working with IC’s professionally, I have never heard them referred to them colloquially as timer chips. Nor am I familiar with the other made up words/phrases you are using to describe standard parts.

My comments are for everyone here, especially those trying to learn something. If you are going to post bad information as fact, be prepared to get called out by somebody here who knows more about it.

I will post and respond as I choose, you are new here and would be better off reading some threads to get a better grasp of the personalities of the difference forums.
 
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#71
shopping (2).jpeg

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:)
 
#72
agedhorse said:
In over 40 years working with IC’s professionally, I have never heard them referred to them colloquially as timer chips. Nor am I familiar with the other made up words/phrases you are using to describe standard parts.
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Agreed, except the 555 timer.

As for the cab, if the delousing worked, why are you building another enclosure? Possible weight saving or creative expression or ....?
 
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#73
agedhorse said:
In over 40 years working with IC’s professionally, I have never heard them referred to them colloquially as timer chips. Nor am I familiar with the other made up words/phrases you are using to describe standard parts.

My comments are for everyone here, especially those trying to learn something. If you are going to post bad information as fact, be prepared to get called out by somebody here who knows more about it.

I will post and respond as I choose, you are new here and would be better off reading some threads to get a better grasp of the personalities of the difference forums.
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Yes please help people keep from electrocuting themselves, ruining their equipment or burning their house down. Myself I have an EE degree but never practiced in the field as I went into IT for 30 plus years. The EE background has served me well in a general sense I suppose, with an engineering approach to problem solving, and also more specifically with some background to do some basic troubleshooting and repair around the house. But most importantly I am aware of what not to touch. I don't have the equipment or years of practical experience to attempt any kind of component level repair or modification, and I appreciate those who do. There is no shame in being aware of our limitations.
 
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#74
Agent0 said:
Yes please help people keep from electrocuting themselves, ruining their equipment or burning their house down. Myself I have an EE degree but never practiced in the field as I went into IT for 30 plus years. The EE background has served me well in a general sense I suppose, with an engineering approach to problem solving, and also more specifically with some background to do some basic troubleshooting and repair around the house. But most importantly I am aware of what not to touch. I don't have the equipment or years of practical experience to attempt any kind of component level repair or modification, and I appreciate those who do. There is no shame in being aware of our limitations.
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My adviser in school (he was a professor in Agricultural Engineering) was very much an expert in legacy power systems, motors, generators and transformers. One thing he used to drill into us is that smart folks, especially engineers and technicians know when to stop and ask for help, before damaging something or hurting someone.

He was the same guy who taught us to be aware of people spewing bull-crapola as fact, because bad information could hurt or kill somebody relying on it.

In IT, how many "royal messes" have you had to deal with that were created by someone under-qualified to me working on it? How many of those messes would have been a simple, easy fix otherwise?
 
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#75
agedhorse said:
My adviser in school (he was a professor in Agricultural Engineering) was very much an expert in legacy power systems, motors, generators and transformers. One thing he used to drill into us is that smart folks, especially engineers and technicians know when to stop and ask for help, before damaging something or hurting someone.

He was the same guy who taught us to be aware of people spewing bull-crapola as fact, because bad information could hurt or kill somebody relying on it.

In IT, how many "royal messes" have you had to deal with that were created by someone under-qualified to me working on it? How many of those messes would have been a simple, easy fix otherwise?
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Definitely some over time. Deleted data etc. Yes I would rather have them ask questions.
 
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