I have a 3 page schematic PDF with schematic, pictorial, and goop drawing, but it's not high enough resolution for me to make out much as far as labels go.
Looking at the GX-120 and GX-212 schematic, it looks like SLM/Crate used the same board with more components soldered in and a the second reverb channel / bright switch circuit etc. installed.
Does anyone have a better copy of the schematic i'm looking for? I attached my copy for reference.
These should be clearer.
Unfortunately that's a different amp with 2 separate gain control knobs and a few other differences.
Honestly I'd take a GX120/212 with parts list if you have one of those. My copy of that schematic doesn't have the SLM part / value list
What is the exact problem you are trying to solve?
We´ll all keep searching, but for servicing, the fuzzy schematic is still kind of readable.
Fuzzy values can be guessed by where they are and what they do.
Agree that layout and parts list are almost unusable.
As a side note, every designer tends to have his pet ideas so many are repeated in different designs, so as you guessed other schematics may help.
So we might help you troubleshoot your amp, what seems to be the problem?
It's pretty "loud" at "idle". I got it for $20, and have a couple of other early 90s Crates (G40CXL, GT50) that I'm scared to accidentally kill trying to "refresh" with multimeter and soldering iron.
This amp though, it was $20, and I'm interested in the GX series' design variations.
There's a cult following for the Crate GX130C... if the GX65 is half that (mono, no Chorus), then maybe I can mod it a little to at least add a bright switch and a couple other little things...
There's someone on an amplifier forum, maybe this one, maybe thegearpage, I've read who absolutely hates the Crate "shape knob" because of how it functions. I think I read that he modified his amp in some way to "fix" the "35 cent" problem Crate decided to make... I'm curious as to that mod as well.
And finally, I have been trying to archive anything I can find about SLM/Crate. The easiest stuff is schematics, but it kills me that I can't find a good one for an amp I now own ::)
Oh! When there's no input cable inserted, there's a feedback loop sound that changes pitch when turning the gain knob.
I think this one is better.
Maybe not. Weird. It looks better before uploading it?
We've gotten spoiled now, used to be that all you could get was photo-copies, which were usually at best, on par with this one. :)
This one if from '98, so probably taken from a copy or early tech scanner and that will be as good as it gets.
The only thing I have any issue with is the labeling of components on the 'pictorial'. If they are not labeled on the board itself, that can make things more time consuming.
Thank you all for your help.
Where should I look for a good "once over" guide for going over it and "refreshing" (i'm thinking things like reflowing solder, etc.), just in general?
Thanks again!
Here's a slightly better one from my paper files but only the main schematic.crate GX-65.gif
Thank you for that! It confirmed my suspicions about the GX-120/212 diagram since my original GX-65 PDF has the parts list - the 2 boards' component values are the same, minus the locations that show "unused" on the GX-65. For any "mods" (bright switch, multiple channel reverb), I can get the values off the 120's schematic.
Thanks again!
Good!!! :tu:
Please post the GX-120/212 diagram here se we can also compare them.
Thanks.
Here's the GX-120 / GX-212 schematic I was referring to.