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4DTV DSR922 Positioner fail - Possible Diode Problem?

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Anonymous
March 10, 2005 4:20:51 PM

Archived from groups: alt.video.satellite.4dtv (More info?)

A good friend's DSR-922 4DTV blew its main fuse last week when he tried to
move the dish. The local repair shop replaced the fuse and at first it
seemed as if all was restored display, receiver functions) but when he
attempts to move the dish, the relays click momentarily and then stop (M1 M2
terminals do NOT provide 36 VDC even for a moment).

We can move the H-H mount with an external 24 VDC supply, and see the pulses
being returned from the positioner, so we have eliminated the outdoor
equipment.

I disconnnected the positioner board to look for anything abnormal and
here's what I found:

Positioner Board is labelled: SD2-V-0 DSR922 Tracker rev 2000.10.27

Transformer, and full-wave rectifier all OK
CR-2 in-circuit measures 3K/3.5K
CR-120 in-circuit measures 2.6K/2.6K
CR-106 in-circuit measures open/open (!)
CR-105 in-circuit measures open/open (!)
CR-104 in-circuit measures short/short

(all these doides look identical to me but for all I know a few could be
zeners)

If somebody has the schematics for this board, perhaps a review if these CRs
could set us on the right path.

Alternately, someone with a similar previous fault could also point us to
resolution.

Failing this, I'll have to figure out where to send this since his dealer
recently went out of business.

Thanks to all who offer any help.

Regards,

Kevin

email: myfamilydotcom@hotmail.com
March 15, 2005 1:58:28 AM

Archived from groups: alt.video.satellite.4dtv (More info?)

On Thu, 10 Mar 2005 13:20:51 +0000, K. Hastings wrote:

> A good friend's DSR-922 4DTV blew its main fuse last week when he tried to
> move the dish. The local repair shop replaced the fuse and at first it
> seemed as if all was restored display, receiver functions) but when he
> attempts to move the dish, the relays click momentarily and then stop (M1 M2
> terminals do NOT provide 36 VDC even for a moment).
>
> We can move the H-H mount with an external 24 VDC supply, and see the pulses
> being returned from the positioner, so we have eliminated the outdoor
> equipment.
>
> I disconnnected the positioner board to look for anything abnormal and
> here's what I found:
>
> Positioner Board is labelled: SD2-V-0 DSR922 Tracker rev 2000.10.27
>
> Transformer, and full-wave rectifier all OK
> CR-2 in-circuit measures 3K/3.5K
> CR-120 in-circuit measures 2.6K/2.6K
> CR-106 in-circuit measures open/open (!)
> CR-105 in-circuit measures open/open (!)
> CR-104 in-circuit measures short/short
>
> (all these doides look identical to me but for all I know a few could be
> zeners)
>
> If somebody has the schematics for this board, perhaps a review if these CRs
> could set us on the right path.
>
> Alternately, someone with a similar previous fault could also point us to
> resolution.
>
> Failing this, I'll have to figure out where to send this since his dealer
> recently went out of business.
>
> Thanks to all who offer any help.
>
> Regards,
>
> Kevin
>
> email: myfamilydotcom@hotmail.com

I had a similar problem with my 920. There is a type of diode that is
actually 2 diodes anode to anode. It is designed to break over at high
voltage and short out any static coming from the positioner. It is
usually across the M1 and M2 terminals. The symbol on the circuit board
will be of 2 diodes pointing at each other. On my 920 it is right above
the cr104 mark on the board. I replaced mine with 2 rectifiers and do not
know if it gives me any static protection but it never gave me any more
trouble. You can cross the number and buy one from NTE.
Hope this helps.

Jim
Anonymous
March 15, 2005 1:29:49 PM

Archived from groups: alt.video.satellite.4dtv (More info?)

There were some posts(and a 920 positioner PCB schematic) in the satforums
about this just recently

http://www.satforums.com

"jim" <jim@nsmeyerpottery.com> wrote in message
news:p an.2005.03.14.22.56.08.967076@nsmeyerpottery.com...
> On Thu, 10 Mar 2005 13:20:51 +0000, K. Hastings wrote:
>
>> A good friend's DSR-922 4DTV blew its main fuse last week when he tried
>> to
>> move the dish. The local repair shop replaced the fuse and at first it
>> seemed as if all was restored display, receiver functions) but when he
>> attempts to move the dish, the relays click momentarily and then stop (M1
>> M2
>> terminals do NOT provide 36 VDC even for a moment).
>>
>> We can move the H-H mount with an external 24 VDC supply, and see the
>> pulses
>> being returned from the positioner, so we have eliminated the outdoor
>> equipment.
>>
>> I disconnnected the positioner board to look for anything abnormal and
>> here's what I found:
>>
>> Positioner Board is labelled: SD2-V-0 DSR922 Tracker rev 2000.10.27
>>
>> Transformer, and full-wave rectifier all OK
>> CR-2 in-circuit measures 3K/3.5K
>> CR-120 in-circuit measures 2.6K/2.6K
>> CR-106 in-circuit measures open/open (!)
>> CR-105 in-circuit measures open/open (!)
>> CR-104 in-circuit measures short/short
>>
>> (all these doides look identical to me but for all I know a few could be
>> zeners)
>>
>> If somebody has the schematics for this board, perhaps a review if these
>> CRs
>> could set us on the right path.
>>
>> Alternately, someone with a similar previous fault could also point us to
>> resolution.
>>
>> Failing this, I'll have to figure out where to send this since his dealer
>> recently went out of business.
>>
>> Thanks to all who offer any help.
>>
>> Regards,
>>
>> Kevin
>>
>> email: myfamilydotcom@hotmail.com
>
> I had a similar problem with my 920. There is a type of diode that is
> actually 2 diodes anode to anode. It is designed to break over at high
> voltage and short out any static coming from the positioner. It is
> usually across the M1 and M2 terminals. The symbol on the circuit board
> will be of 2 diodes pointing at each other. On my 920 it is right above
> the cr104 mark on the board. I replaced mine with 2 rectifiers and do not
> know if it gives me any static protection but it never gave me any more
> trouble. You can cross the number and buy one from NTE.
> Hope this helps.
>
> Jim
>
Anonymous
March 16, 2005 1:16:48 AM

Archived from groups: alt.video.satellite.4dtv (More info?)

Many thanks to those who responded, or emailed me directly. CR104 is a MOV
and definitely was the culprit. A pocketful is on order. Thanks to all on
behalf of my buddy - he's up and running again.

Kevin


"K. Hastings" <myfamilydotcom@hotmail.com> wrote in message
news:TQXXd.17258$oh4.631005@ursa-nb00s0.nbnet.nb.ca...
> A good friend's DSR-922 4DTV blew its main fuse last week when he tried to
> move the dish. The local repair shop replaced the fuse and at first it
> seemed as if all was restored display, receiver functions) but when he
> attempts to move the dish, the relays click momentarily and then stop (M1
M2
> terminals do NOT provide 36 VDC even for a moment).
>
> We can move the H-H mount with an external 24 VDC supply, and see the
pulses
> being returned from the positioner, so we have eliminated the outdoor
> equipment.
>
> I disconnnected the positioner board to look for anything abnormal and
> here's what I found:
>
> Positioner Board is labelled: SD2-V-0 DSR922 Tracker rev 2000.10.27
>
> Transformer, and full-wave rectifier all OK
> CR-2 in-circuit measures 3K/3.5K
> CR-120 in-circuit measures 2.6K/2.6K
> CR-106 in-circuit measures open/open (!)
> CR-105 in-circuit measures open/open (!)
> CR-104 in-circuit measures short/short
>
> (all these doides look identical to me but for all I know a few could be
> zeners)
>
> If somebody has the schematics for this board, perhaps a review if these
CRs
> could set us on the right path.
>
> Alternately, someone with a similar previous fault could also point us to
> resolution.
>
> Failing this, I'll have to figure out where to send this since his dealer
> recently went out of business.
>
> Thanks to all who offer any help.
>
> Regards,
>
> Kevin
>
> email: myfamilydotcom@hotmail.com
>
>
>
!