Re: TEK 475 voltage issues.

Tony G4NGV

Sorry, there was a resistor with 104V on it and this resistor was touching
the groundplane of the PCB.

On Thu, Mar 28, 2019 at 6:46 AM Tony G4NGV via Groups.Io <tonyvirago2=> wrote:

On mine, I had a fault where the 104 was dragging down the 110v
The 104v was shorting/arcing to the ground plane of the pcb as it was
touching and over the years the paint on the R wore off?. I monitored the
104V while lifting parts of the cct to eliminate them. Hope this helps.
Tony UK


On Wed, Mar 27, 2019 at 11:01 PM Glen Layne <gelayne@...> wrote:

Hey all. I'm new to the group and trying to restore 475 scope. when I
got it, 2 of the voltages were way off. The +110 was about +19 and the
+105/160 was coming in at +10.7. The other voltages were fine. So, I
ordered and replaced the 6 main caps. Q1497 was bad and I replaced it.
Now the +110 is coming at 86.1 and the +105/160 is still at 10.7.

So, the scope appears to work. Surprisingly well considering the voltage
issues I still have. I can't find what's bringing down the +110 and the
+105/160 at 10.7 can't be good. Q1456 (darlington) runs pretty hot and
it's on the +105 rail.

On occasion, the trace will shrink to postage stamp size. I can usually
adjust the Horizontal position all the way to the right and it will come
out of the postage stamp mode even though it may not be a stable trace.
Sometimes, I double push the 10x Mag and fiddle with the Horiz position
get things back working.

Any ideas what to do next?

*From November 2013 I am using @Tonyvirago
<@Tonyvirago> as my email address.*
*My o2 email is going soon.*

*From November 2013 I am using @Tonyvirago
<@Tonyvirago> as my email address.*
*My o2 email is going soon.*

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