[TechAssist] Re: TOA " 900 series " (A-912A) mono PA amp no output(in protect)
- From: "Shoreline Electronics" <jstielau@xxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sun, 5 Feb 2006 13:25:54 -0500
http://www.toaelectronics.com/disc/manuals/A-903_6_12A.pdf
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@xxxxxxxx
========================
----- Original Message -----
From: "Philip Bader" <pbader@xxxxxxxxxxxxxxx>
To: "Techassist" <techassist@xxxxxxxxxxxxx>
Sent: Sunday, February 05, 2006 12:57 PM
Subject: [TechAssist] TOA " 900 series " (A-912A) mono PA amp no output(in
protect)
> (Guys, thanks for the help on the Zenith PTV I submitted a few days
> ago.All
> good info.)
> Now:
> A school I was called out to last week has this Public address amp up in
> the
> press box for the sports field. Has power,front meter lights but the relay
> never clecks on(in protect). It's a silver finish anout the size of a
> large
> home amp.
> All four power outputs are OK. There are a number of driver transistors on
> a
> seperate board shorted.Some have been replaced a number of years ago,some
> are NTE's. I have no diagram or even a parts list.I would like to replace
> them with original transistor part numbers.
> List of bad transistors I found and the numbers on them:
> Q101, NTE90
> Q103, NTE123AP
> Q104, NTE123AP
> Q106, B647
> Q108, D667
> other small surrounding transistors that "seem" to check OK:
> Q103, NTE90
> Q105, B647
> Q109, D667
> Q112, (?)
> Even a parts list would help.There are a few dark resistors as well.
> This looks pretty heavy duty with a huge audio output transformer.
> Even tho the previous tech used NTE's they have held up good for about 3
> years.
> Schemo or parts list please? Any assist welcomed...
> Thanks.
> Phil
> Philip Bader
> Polk County School Board
> Electronics Shop, Bartow,Fl.
> (former owner, Jan Phyl TV Inc.,Winter Haven, Fl. from 1976-2006)
> email: pbader@xxxxxxxxxxxxxxx
> phone # given by request
>
>
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