Author Topic: Can anyone give me a hand (e-hand, even) biasing a screamer? (Read 8189 times)

Kilby · « **Reply #15 on:** April 14, 2007, 12:44:37 PM »

Quote from: Muzzzz

I don't get it... :? :oops:

The daily mail is very biased in regard to politics

Baically theyre somewhat to the right of Hitler

HTH AMPS · « **Reply #16 on:** April 14, 2007, 03:34:39 PM »

try this on for size...

http://www.angelfire.com/electronic/vtubes/Theory/JCM900Biasing.html

:twisted:

dave_mc · « **Reply #17 on:** April 14, 2007, 09:40:00 PM »

Quote from: Muzzzz

I don't get it... :? :oops:

the daily mail is a newspaper, with quite a right wing bias.

Quote from: noodleplugerine

Quote from: dave_mc
let it read the daily mail.

You win the internet.

*fist pump*

"that's what i'm talkin' about!"

EDIT: lol at rob, maybe that's a little far... (though didn't they support mosely back in the day? :lol: )

_tom_ · « **Reply #18 on:** April 14, 2007, 09:51:22 PM »

^

:lol:

Kilby · « **Reply #19 on:** April 14, 2007, 10:06:57 PM »

Quote from: dave_mc

lol at rob, maybe that's a little far... (though didn't they support mosely back in the day? :lol: )

Nope they disowned him for being too soft

MDV · « **Reply #20 on:** April 15, 2007, 02:59:56 AM »

Hunter, that was a massive help, thank you.

I think I can cobble together this information now to get this done. Its all making much more sense now. I'll print that off on A3 at work and sit and correlate it with the actual board for a bit.

All this just to turn one bloody screw by the right amount!!

P.S. Dave: the screamer reads the sun, but never gets past page 3!

The TSL is well biased...I'll have to check for daily mails in the back of it!

dave_mc · « **Reply #21 on:** April 15, 2007, 07:16:09 PM »

^, ^ ^ and ^ ^ ^

:lol:

MDV · « **Reply #22 on:** April 16, 2007, 09:29:13 PM »

Well, I think I fried my multimeter :lol:

Its just...well was just an argos thing.

I'm still not sure what points to test :lol:

Its not clear what goes where looking at the back of the PCB: you cant see the componets, wires just end and what have you. First time inside an amp. More confusion than doing.

Anyway. I hope these are clear...

This be re-post of hunters most good schematic

http://www.thegutbusters.com/temp/ENGLBIAS.pdf

This be bias trim pot and valves

This be output transformer connections from valves

This be whole thing

This be dead

Can anyone help me, in baby talk, find where to check the idle current please? It would be much appreciated!

P.S. HTH, your post on the JCM900 was alarming. Please tell me I dont need to solder anything yet! I'd like to do this with a DMM (a new one, not touching THAT contact again: interesting way to find which connection the plate voltage runs through to the valves though).

P.P.S. I havent changed the valves yet and played though it: its fine. Sounds better even: I uderbiased it from factory just a tad (in case...I dunno...I am actually quite cautious about this stuff...bar blatent disregard for the welfare of my multimeter) took some harshness that started this whole thing out of it).