[TechAssist] Re: TOA " 900 series " (A-912A) mono PA amp no output(in protect)
- From: "Philip Bader" <pbader@xxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sun, 5 Feb 2006 16:03:56 -0500
That is it! Even three diagrams. Thanks so much.I burned a CD and printed
the diagrams already.Ready for Monday.
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
----- Original Message -----
From: "Shoreline Electronics" <jstielau@xxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Sunday, February 05, 2006 1:25 PM
Subject: [TechAssist] Re: TOA " 900 series " (A-912A) mono PA amp no
output(in protect)
> 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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