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Sony (Sun) GDM20E20 Monitor - flashing standby but done boardswap

  • Thread starter System Alchemist
  • Start date
S

System Alchemist

Jan 1, 1970
0
Sony (Sun) GDM20E20 Monitor - flashing standby (1Hz 50% duty)
which I think means B+ problem.

However I have swapped all the boards (A, D and G)from a good
monitor into the duffo one and still get the same result.

This leaves the tube and the neck gubbins which is all soldered
and glued in place.

I don't have any schematics etc for this monitor (do you?!) or
any experience of repairing monitors.

Any ideas where to look with this one?

---Paul
 
C

CJT

Jan 1, 1970
0
System said:
Sony (Sun) GDM20E20 Monitor - flashing standby (1Hz 50% duty)
which I think means B+ problem.

However I have swapped all the boards (A, D and G)from a good
monitor into the duffo one and still get the same result.

This leaves the tube and the neck gubbins which is all soldered
and glued in place.

I don't have any schematics etc for this monitor (do you?!) or
any experience of repairing monitors.

Any ideas where to look with this one?

---Paul
If it's gone into protection mode, perhaps the CRT is drawing too much
current.

I doubt it's worth fixing, especially considering the price of working
used ones.
 
S

System Alchemist

Jan 1, 1970
0
CJT said:
If it's gone into protection mode, perhaps the CRT is drawing too much
current.

I doubt it's worth fixing, especially considering the price of working
used ones.

I am happy to invest my time to avoid creating landfill prematurely if
this is fixable. The previous user found that a strategic nudge would
bring it to life but since transporting the monitor this no longer has
the desired effect. The monitor did work for about a week when I got
it.
---Paul
 
A

Andy Cuffe

Jan 1, 1970
0
I am happy to invest my time to avoid creating landfill prematurely if
this is fixable. The previous user found that a strategic nudge would
bring it to life but since transporting the monitor this no longer has
the desired effect. The monitor did work for about a week when I got
it.
---Paul


Have you double checked that the horizontal and vertical sync are
getting to the monitor? Check the cable for opens. Also, I think
this monitor can't go below SVGA resolution without shutting down. If
this is the one with all the controls on a little IR remote, it won't
do VGA and DOS text modes.
Andy Cuffe
[email protected]
 
J

Jerry G.

Jan 1, 1970
0
This sounds like the CRT is pulling too much current. The CRT is not worth
replacing in these.

--

Jerry G.
======


Sony (Sun) GDM20E20 Monitor - flashing standby (1Hz 50% duty)
which I think means B+ problem.

However I have swapped all the boards (A, D and G)from a good
monitor into the duffo one and still get the same result.

This leaves the tube and the neck gubbins which is all soldered
and glued in place.

I don't have any schematics etc for this monitor (do you?!) or
any experience of repairing monitors.

Any ideas where to look with this one?

---Paul
 
S

System Alchemist

Jan 1, 1970
0
This sounds like the CRT is pulling too much current. The CRT is not worth
replacing in these.

Recently acquired info suggests that this may be:
Horizontal/Vertical deflection failure, thermal protector

Given that a board swap doesn't help, any suggestions what I should
poke (ideally with the monitor off) to narrow this down?

Any ideas on how the deflection failure is detected?
Likewise, what does the thermal protector protect?

TIA
---Paul
 
C

CJT

Jan 1, 1970
0
System said:
Recently acquired info suggests that this may be:
Horizontal/Vertical deflection failure, thermal protector

Given that a board swap doesn't help, any suggestions what I should
poke (ideally with the monitor off) to narrow this down?

Any ideas on how the deflection failure is detected?
Likewise, what does the thermal protector protect?

TIA
---Paul

I think they work a lot like the protection circuit on a Sony TV --
beam current (and potentially other parameters) are monitored and
if they exceed parameters trigger a signal that shuts down the
device.
 
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