Success!!! I really appreciate all of the help from Tristan and others.
Nice to have my clock back.
Turns out the trace from blanking from pin 9 of the 74HC74 takes a very
long route around the edge of the board in reaching pin 2 of U17 (6N137).
There was a small defect in the copper trace
, October 27, 2021 at 10:48:16 AM UTC-4 GEK wrote:
> I probably do have a 10meg resistor down in my cellar, time to dig. I
> wasn't sure if I'd need to create an actual voltage divider with 2
> resistors/ground wire so that's helpful. I'd hate to destroy a Fluke...
>
> On Wednes
ividing those 2 measurements will give you a ratio close to 2.0, and you
> can use that when measuring your high voltage.
>
>
> On Tuesday, October 26, 2021 at 8:40:54 PM UTC-7 GEK wrote:
>
>> Thanks everyone for the hints, I'll look more closely at the HV - I'm a
>&g
dedicated to the grid and it
>> is referenced to the cathode. Although you have now replaced most of the
>> potentially offending components unless you have an open winding on the
>> transformer. You could check the resistance across pins 4,5 and 6 of the
>> transfo
ttps://www.tindie.com/products/howchon/osc45-oscilloscope-clock-kit-for-many-crt-types/
>>>
>>>
>>>
>>>
>>>
>>> ~
>>> *mcve...@gmail.com*
>>>
>>>
>>> On Wed, Oct 20, 2021 at 4:16 AM GEK wrote:
>>>
>&g
ed to look at the D35-38 and C52 & C53.
>
> - Tristan
>
> On Wednesday, October 20, 2021 at 12:42:53 PM UTC+10 GEK wrote:
>
>> Tristan -
>>
>> Thanks for those hints. the BLNK signal is pulsing at 60hz, and I
>> swapped Q13 without any change. I also so
Tristan -
Thanks for those hints. the BLNK signal is pulsing at 60hz, and I swapped
Q13 without any change. I also socketed U17 (6N137) while waiting for a
replacement to arrive. Removing U17 from the circuit leaves the display
unchanged, so it does appear that the blanking circuit is the
r 18, 2021 at 4:53:06 PM UTC-7 GEK wrote:
>
>> I've been unsuccessful in reaching David Forbes, so thought I would ask
>> the group for help.
>>
>> My SC200C has been "unhealthy" for a while now, and I'm trying to get it
>> running properly.
>>
