[TechAssist] Re: GE VCR VG2021 - ZD6 Shorting
- From: "David Lessard" <mr_fixit@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Fri, 26 Mar 2004 17:21:33 -0000
With zener ZD6 removed I measure 83VDC across C17 which is parallel to
ZD6. This seems a bit high. You're probably right about the over voltage
condition because when I fired up the SMPS on the bench (out of the VCR)
ZD5 blew too, removed it and measured 36VDC across where it should be.
As far as I can tell the opto checks OK. What is IC2, PCB markings are
C-A-R, is this an SCR? By the way, can you confirm the values of ZD5 and
ZD6?
Thanks,
David Lessard
Alexandria Electronics
Ontario, Canada
mr_fixit@xxxxxxxxxxxx
-----Original Message-----
From: techassist-bounce@xxxxxxxxxxxxx
[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of peggs
Sent: Thursday, March 25, 2004 11:49 PM
To: techassist@xxxxxxxxxxxxx; techassist@xxxxxxxxxxxxx
Subject: [TechAssist] Re: GE VCR VG2021 - ZD6 Shorting
If that Zener is in the secondary of the PS,you probably have an
overvoltage condition.
IOW,the Primary is being driven wide open.
Check opto-isolator.
it seems I had an IC2 in the secondary causing this condition once
Peggs
At 07:44 AM 3/26/04, David Lessard wrote:
>This VCR was in for service a few weeks ago, SMPS was dead, replaced
the
>following:
>
>Q1 - C4418
>Q2 - ECG382
>D02 - IN4148
>C09 - 22uf/16v
>
>Then the display was blinking when powered up, found ZD6 leaky,
replaced
>it with 33V/1W zener (I think this is supposed to be a 43V zener?),
>anyway, ZD6 blows within a minute of VCR being powered up. What could
be
>causing this? What circuit(s) does this supply?
>
>Thanks in advance,
>
>David Lessard
>Alexandria Electronics
>Alexandria, Ontario, Canada
>mr_fixit@xxxxxxxxxxxx
>
>
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