Do I actually have a Frankenstein?? [message #21276] |
Tue, 26 August 2014 09:55 |
Jerrybass1955
Messages: 45 Registered: August 2014 Location: NC
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I have been working on the tremolo and reverb issues with my K100-2 and as I dig in, I am finding some unusual things.
Like:
Significant numbers of resistor values not the same as either Rev. 3 or Rev. 4 schematics. I have found three in the reverb circuit and haven't really looked much elsewhere. None of the resistors look like obvious replacements. R162 was 33K, R165 was 150 ohms and R170 was 100 ohms (instead of 15K!).
I found an extra part - a 100K resistor that may be connected to the reverb input to ground. Maybe there are more!
Transistor locations are slightly different than the transistor location map would suggest.
Serial number is 33804
PCB says "KEI-1 PC104"
Thought I had a rev. 4, but not so sure now. What do you think? Anyone know what I have?
If it is a Frankie, is there any documentation out there that might be useful? Suggested modifications?
Any suggestions on whether I should update the values to match the Rev. 4 schematic? (already did some of that in the reverb circuit with somewhat positive results - e.g., changed R 170 from 100 ohms to 15K!)
Jerry
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Re: Do I actually have a Frankenstein?? [message #21279 is a reply to message #21276] |
Tue, 26 August 2014 11:56 |
chicagobill
Messages: 2005 Registered: April 2003
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Senior Member |
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The Frankenstein or Frankie terms come from the shape of the head cabinet of the earliest K200 amps. In order to have a space to mount the reverb tank, the top section of the front panel was made wider than the side panels, so when looking at the front of the amp it had a tall forehead just like the imagery of the Frankenstein monster.
During this time period the model numbers were all based upon the brand of speaker and the list price of the amp/speaker and what features the amp had. So a model C595 would have no fx and CTS speakers. A model C695RV would have Reverb and Vibrato with CTS speakers, etc. Because all of the prices ended with 95 these amps are sometimes referred to as 95 series amps. When the K200A series amps were introduced, there were too many different models to continue using the list price as the model number, so a new numbering system started. Unfortunately the 95 numbers were kept for the PA heads, so there are some 95 PA amps that are not Frank circuits, but are early A-series circuits. These amps are easily recognized by the lack of the tall forehead case.
As for your K100 questions, your amp is a different version than either the ver. 3 or 4. So if it is an earlier version you can go through the amp and convert it to a ver.4 or you can just try and fix it as is. I don't own any K100s and other than basic tech info, I have no real insight to help guide you.
[Updated on: Tue, 26 August 2014 11:58] Report message to a moderator
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Re: Do I actually have a Frankenstein?? [message #21290 is a reply to message #21287] |
Wed, 27 August 2014 12:28 |
chicagobill
Messages: 2005 Registered: April 2003
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Senior Member |
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Those numbers are correct per the schematic. There is a note on the schematic that states that the two driver transistors should have clip on heat sinks. Your amp may have been built before that was added by the factory.
I'll have to look for any cross references to those numbers and add them to the list.
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