Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Eico 235 VTVM
#1

I have gone through the whole meter and replaced all parts needed. The meter works but when referring to the manual it states to adjust R23 to get a zero meter if you don’t when selecting the function switch. I tested R23 it reads around 11K but when testing to adjust the zero needle it does nothing.Also thinking of a battery eliminator circuit to replace the D cell battery.


Attached Files Image(s)
       
#2

Hi. It's important to remember that the potentiometer may measure 11K, but a measurement should be taken across one of the end terminals to the center terminal while moving the control through it's entire swipe. Look for a smooth change in resistance. Quite often the wiper will have dirt and have intermittent contact. This can usually be corrected with an electronic cleaner spray. Here's a link to the battery eliminator I have used in my meters.
https://forums.qrz.com/index.php?threads...it.650848/
I have also used the LM317 adjustable regular circuit but this one works very well and is simpler.
#3

Hi Rod, I did clean all the controls with contact cleaner and measured resistance from the center to the outer terminals and from outside to outside. The pin 1 and 2 measure from 3 ohm to 11k with 2 interruptions while turning no reading then resumes while turning. Finding one like it should be fun. Thanks for the link ill check that out.
#4

With 2 interruptions it's defective. It will have a tendency to fail right where the wiper sits for long periods of time. You might be able to take it out, remove the back cover and inspect the insides. Not usually a difficult task. You just have to be gentle pulling back the cover prongs. If you get the cover off use some alcohol with a soft brush to gently wipe it clean.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Hi OSanders, Look carefully at the band switch. Turn it slowly and "wiggle" it around the desired band. ...MrFixr55 — 12:33 AM
5U4 vs 5Z4 tubes
I think that RCA and GE introduced metal tubes in the USA in 1936.  I don't know if they were being made by RCA, GE or b...MrFixr55 — 11:20 PM
Philco 42-345 Restoration/Repair
Vlad95, Thank you for the stringing guides and wow there are so manyosanders0311 — 06:01 PM
5U4 vs 5Z4 tubes
A pre war Hallicrafters, and an early one too, very nice! 1936 is pretty early for metal tubes too, which would explain ...Arran — 05:58 PM
Philco 42-345 Restoration/Repair
Thanks Rod, "When you hear the background hiss and no station it usually indicates that the oscillator quit" ...osanders0311 — 05:52 PM
Philco 42-345 Restoration/Repair
RodB :beerchug:Vlad95 — 10:22 AM
Philco 42-345 Restoration/Repair
Vlad, you nailed it. Swiss and German roots.RodB — 09:54 AM
5U4 vs 5Z4 tubes
Well this is a Hallicrafters SX/9 circa 1936. No real issues so far although I dodged a real bullet with a cap that was...bridkarl — 07:59 AM
5U4 vs 5Z4 tubes
The pinout is the same but the 5U4 has a 3 amp filament, verses 2 amps or less on the 5Z4. I think that the pinout of a ...Arran — 12:04 AM
Philco 42-345 Restoration/Repair
By the way. osanders0311 Take a look here: Dial cord stringing Guides May be here you can fount correct string settin...Vlad95 — 11:15 PM

[-]
Who's Online
There are currently 1307 online users. [Complete List]
» 1 Member(s) | 1306 Guest(s)
Avatar

>