SB 610 Scope Power Transformer
 

I have been tinkering with a Heath SB 610 Monitor Scope with the
apparently fairly common problem of a Blown Power Transformer.
I read somewhere of people using an "outboard" transformer to work
around this problem. So, which winding is it that blows: the 215 VAC
or the 600 VAC. And can one just disconnect the blown winding and
connect the additional transformer at the appropriate point? Thanks
for any info.

Do you have the assembly manual?...

If the power transformer is blowing... I must admit I don't have a schematic
to follow.. can you disconnect the load from the power supply and see if the
transformer gets warm... my rational is that the output capacitors might be
leaking excessively and may need to be replaced...

I had a battery charger that frequently blew the bridge rectifiers until I
removed the output capacitor.. after that the bridge ran quite cool...
comparatively speaking...

Larry



"Mike" wrote in message
oups.com...
I have been tinkering with a Heath SB 610 Monitor Scope with the
apparently fairly common problem of a Blown Power Transformer.
I read somewhere of people using an "outboard" transformer to work
around this problem. So, which winding is it that blows: the 215 VAC
or the 600 VAC. And can one just disconnect the blown winding and
connect the additional transformer at the appropriate point? Thanks
for any info.

Mike wrote:
I have been tinkering with a Heath SB 610 Monitor Scope with the
apparently fairly common problem of a Blown Power Transformer.
I read somewhere of people using an "outboard" transformer to work
around this problem. So, which winding is it that blows: the 215 VAC
or the 600 VAC. And can one just disconnect the blown winding and
connect the additional transformer at the appropriate point? Thanks
for any info.

I worked for some time trying to replace a defective transformer in one
of these units. Since I could never find a suitable replacement trans.
I attempted to use two transformers to make up the necessary
voltages..Not enough room, I gave up as a hopeless case.. The original
transformer was so small,winding (wire size) was so small,they opened
up after 20/30 years.Usually the 600 v winding goes out.. Good Luck 73
W4PQW

I have four of these in the shop waiting to be rewound. All have the same
problem, high voltage winding burnt.
Regards,
Gary...WZ1M
wrote in message
oups.com...

Mike wrote:
I have been tinkering with a Heath SB 610 Monitor Scope with the
apparently fairly common problem of a Blown Power Transformer.
I read somewhere of people using an "outboard" transformer to work
around this problem. So, which winding is it that blows: the 215 VAC
or the 600 VAC. And can one just disconnect the blown winding and
connect the additional transformer at the appropriate point? Thanks
for any info.

I worked for some time trying to replace a defective transformer in one
of these units. Since I could never find a suitable replacement trans.
I attempted to use two transformers to make up the necessary
voltages..Not enough room, I gave up as a hopeless case.. The original
transformer was so small,winding (wire size) was so small,they opened
up after 20/30 years.Usually the 600 v winding goes out.. Good Luck 73
W4PQW

In article .com,
wrote:

I worked for some time trying to replace a defective transformer in one
of these units. Since I could never find a suitable replacement trans.
I attempted to use two transformers to make up the necessary
voltages..Not enough room, I gave up as a hopeless case.. The original
transformer was so small,winding (wire size) was so small,they opened
up after 20/30 years.Usually the 600 v winding goes out.. Good Luck 73
W4PQW

I believe Hammond now makes an appropriate replacement transformer. Yes,
the power transformer is blown on a _lot_ of old Heath scopes. For the
cost of a Hammond, though, you can get a nice Tektronix at a hamfest.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

WHY do these continously wipe out?
Any one KNOW or can offer prevention measure?
Resistive load, current clamp--what?
AL

"larry" wrote in message
...
Do you have the assembly manual?...

If the power transformer is blowing... I must admit I don't have a
schematic
to follow.. can you disconnect the load from the power supply and see if
the
transformer gets warm... my rational is that the output capacitors might
be
leaking excessively and may need to be replaced...

I had a battery charger that frequently blew the bridge rectifiers until I
removed the output capacitor.. after that the bridge ran quite cool...
comparatively speaking...

Larry



"Mike" wrote in message
oups.com...
I have been tinkering with a Heath SB 610 Monitor Scope with the
apparently fairly common problem of a Blown Power Transformer.
I read somewhere of people using an "outboard" transformer to work
around this problem. So, which winding is it that blows: the 215 VAC
or the 600 VAC. And can one just disconnect the blown winding and
connect the additional transformer at the appropriate point? Thanks
for any info.

AL G. wrote:
WHY do these continously wipe out?
Any one KNOW or can offer prevention measure?
Resistive load, current clamp--what?
AL


Because Heath used some of the crappiest suppliers
for some of their transformers. If you wind a HV
winding with very fine wire, and allow any of the
individual strands of wire to pull tight, when the
transformer gets warm and expands, the wire will be
stressed and eventually break.

There is nothing you can do short of rewinding or
replacing the transformer.

-Chuck

AL G. wrote:
WHY do these continously wipe out?
Any one KNOW or can offer prevention measure?
Resistive load, current clamp--what?

Almost certainly a design problem. Heath was not exactly known to use
the highest quality parts in the first place. I suspect that it's a matter
of insulation breakdown on the high voltage winding, so that a PTO
thermistor in series with the primary to reduce inrush current won't
help much.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."