VintageKustom.com
VintageKustom.com is your source for literature and information on the tuck-and-roll vintage Kustom amps from the 60's and 70's, as well as their related products such as guitars and organs . We provide a webboard for help with kustom gear history, technical information and repairs as well as discussions with other collectors.
Home » VintageKustom.com » Repairing Kustom Amps » K200b-1 DEAD Bright Channel (Dead Bright Channel)
Show: Today's Messages :: Polls :: Message Navigator
Switch to threaded view of this topic Create a new topic Submit Reply
K200b-1 DEAD Bright Channel [message #25427] Tue, 16 August 2016 22:41 Go to next message
gregp is currently offline  gregp
Messages: 13
Registered: August 2016
Junior Member
I just picked this blue sparkle beauty up! Normal Channel is fine. Bright Channel DOA!
I tried the Bright switch trick - cleaning, etc. to no avail.
I do get a slight popping when activating the Bright knob and I get hiss when turning up the treble. Otherwise is dead?
Anyone care to point me in the right direction on next steps?

Report message to a moderator

Re: K200b-1 DEAD Bright Channel [message #25428 is a reply to message #25427] Wed, 17 August 2016 06:34 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4775
Registered: June 2004
Location: NY
Senior Member
9 times out of 10 the first transistor off of the input Jack has been popped by being hit by too much signal level!
These transistors cost 25 cents and the shipping cost are 500% more, lol!

Of course if the amp has been worked on and screwed up then things could get deep real fast !

Have you worked on circuits before other then soldering wires and such?

[Updated on: Wed, 17 August 2016 06:35]

Report message to a moderator

Re: K200b-1 DEAD Bright Channel [message #25429 is a reply to message #25428] Wed, 17 August 2016 07:54 Go to previous messageGo to next message
gregp is currently offline  gregp
Messages: 13
Registered: August 2016
Junior Member
Yeah, old hand wired stuff and I have built a few.... but nothing solid state.
Guess I better pull a schematic and figure out the value of that transistor?

If I got you right, that one is right on top of the board after an orange drop and ceramic disc cap?

[Updated on: Wed, 17 August 2016 07:57]

Report message to a moderator

Re: K200b-1 DEAD Bright Channel [message #25430 is a reply to message #25427] Wed, 17 August 2016 09:19 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4775
Registered: June 2004
Location: NY
Senior Member
The Transistor has a 47 pf cap across its base and collector , the Emitter leg is the one on the schematic with a arrow on it and the volume control is in the Emitter leg also!

Report message to a moderator

Re: K200b-1 DEAD Bright Channel [message #25476 is a reply to message #25427] Thu, 25 August 2016 20:17 Go to previous message
gregp is currently offline  gregp
Messages: 13
Registered: August 2016
Junior Member
Well. I replaced the PET 8002 with a 2N3904..... while it DID bring the BRIGHT channel back to life, its clearly either not right or there are further issues.
The dead Bright channel now works, However,
It works best in the LOW input, the Bright input is weak and thin
Also
when you engage the BRIGHT Boost, the volume drops significantly.
Finally, there is also a lot of HISS, particularly the higher the TREBLE is turned up?

Any thoughts?

Report message to a moderator

  Switch to threaded view of this topic Create a new topic Submit Reply
Previous Topic: amp seems to get distorted as volume is turned up
Next Topic: Re-coning Speaker
Goto Forum:
  

-=] Back to Top [=-
[ Syndicate this forum (XML) ] [ RSS ]

Current Time: Sat Nov 16 09:58:21 EST 2024
.:: Contact :: Home ::.

Powered by: FUDforum 3.1.3.
Copyright ©2001-2023 FUDforum Bulletin Board Software