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FG504 and failed Q270 (SPS2927)

NigelP
 

My FG504 had suddenly died when I tried to use it yesterday (no output basically). After a lot of probing around I discovered that Q270 on the A3 Loop board had failed. It's specified as 151-0438-00, a selected SPS2927. I'm sure this one has come up before but I can't find a spec or alternative device.... can anyone suggest a suitable device please. I've put in a BC212L just to prove the fault diagnosis but it would be nice to get the right part.

In the course of trouble-shooting I wasn't sure where to start. The manual describes the complete workings but doesn't say how/where the triangle waveform actually starts off in life! I eventually realised the whole thing was a closed loop (A3 LOOP Board should have been a clue :-)), which doesn't help diagnosis..... had to go probing all transistor terminals looking for trouble. Can anyone explain the signal generation process in a simple fashion?

 

From the Tek semiconductor data book, the 151-0438-00 was superseded by
151-0712-00, both of which cross to an MPSH81.

Cheers,
Dave M


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FG504 and failed Q270 (SPS2927)
From: NigelP
Date: Sat, 28 Apr 2018 11:25:43 CDT
My FG504 had suddenly died when I tried to use it yesterday (no output
basically). After a lot of probing around I discovered that Q270 on the A3
Loop board had failed. It's specified as 151-0438-00, a selected SPS2927.
I'm sure this one has come up before but I can't find a spec or
alternative device.... can anyone suggest a suitable device please. I've
put in a BC212L just to prove the fault diagnosis but it would be nice to
get the right part.

NigelP
 

Many thanks for that; I'll look it up..... might even have some in the transistor collection :).

Nigel Pritchard

ArtekManuals
 

Many thanks for what ? Relevant prior post not included ????

On 4/29/2018 7:17 AM, NigelP wrote:
Many thanks for that; I'll look it up..... might even have some in the transistor collection :).

Nigel Pritchard





--
Dave
Manuals@...
www.ArtekManuals.com

 

Wasn't because I didn't try... I made sure to quote the original post in my reply, but I guess groups.io scrubbed it. I replied by "Reply to Group" at the bottom of the original message (I get the digest format), and made sure to copy the original message text into my reply..
Anyway, sorry for the confusion.

Cheers,
Dave M

On Sun, Apr 29, 2018 at 05:43 am, Artekmedia wrote:


Many thanks for what ? Relevant prior post not included ????

On 4/29/2018 7:17 AM, NigelP wrote:
Many thanks for that; I'll look it up..... might even have some in the
transistor collection :).

Nigel Pritchard
--
Dave
Manuals@...
www.ArtekManuals.com


 

Well, it happened again. I made sure to click the little "Quote Whole Post" icon before replying, but the quoted text didn't make it into my reply. Groups.io gone bonkers, or is it me? What am I doing wrong?

Dave M

On Sun, Apr 29, 2018 at 07:36 am, David M wrote:


Wasn't because I didn't try... I made sure to quote the original post in my
reply, but I guess groups.io scrubbed it. I replied by "Reply to Group" at
the bottom of the original message (I get the digest format), and made sure to
copy the original message text into my reply..
Anyway, sorry for the confusion.

Cheers,
Dave M

On Sun, Apr 29, 2018 at 05:43 am, Artekmedia wrote:


Many thanks for what ? Relevant prior post not included ????

On 4/29/2018 7:17 AM, NigelP wrote:
Many thanks for that; I'll look it up..... might even have some in the
transistor collection :).

Nigel Pritchard
--
Dave
Manuals@...
www.ArtekManuals.com


Chuck Harris
 

It worked both times.

-Chuck Harris

David M wrote:

Well, it happened again. I made sure to click the little "Quote Whole Post" icon before replying, but the quoted text didn't make it into my reply. Groups.io gone bonkers, or is it me? What am I doing wrong?

Dave M

On Sun, Apr 29, 2018 at 07:36 am, David M wrote:


Wasn't because I didn't try... I made sure to quote the original post in my
reply, but I guess groups.io scrubbed it. I replied by "Reply to Group" at
the bottom of the original message (I get the digest format), and made sure to
copy the original message text into my reply..
Anyway, sorry for the confusion.

Cheers,
Dave M

On Sun, Apr 29, 2018 at 05:43 am, Artekmedia wrote:


Many thanks for what ? Relevant prior post not included ????

On 4/29/2018 7:17 AM, NigelP wrote:
Many thanks for that; I'll look it up..... might even have some in the
transistor collection :).

Nigel Pritchard

 

Probably something weird about the digest mode? I'll switch to Individual Emails for a day or so and see if it changes.

Dave M

On Sun, Apr 29, 2018 at 08:44 am, Chuck Harris wrote:


It worked both times.

-Chuck Harris

David M wrote:
Well, it happened again. I made sure to click the little "Quote Whole Post"
icon before replying, but the quoted text didn't make it into my reply.
Groups.io gone bonkers, or is it me? What am I doing wrong?

Dave M

On Sun, Apr 29, 2018 at 07:36 am, David M wrote:


Wasn't because I didn't try... I made sure to quote the original post in
my
reply, but I guess groups.io scrubbed it. I replied by "Reply to Group" at
the bottom of the original message (I get the digest format), and made sure
to
copy the original message text into my reply..
Anyway, sorry for the confusion.

Cheers,
Dave M

On Sun, Apr 29, 2018 at 05:43 am, Artekmedia wrote:


Many thanks for what ? Relevant prior post not included ????

On 4/29/2018 7:17 AM, NigelP wrote:
Many thanks for that; I'll look it up..... might even have some in the
transistor collection :).

Nigel Pritchard