Eico 221 VTVM Reguild - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd October 2013, 11:24 AM   #1
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
Default Eico 221 VTVM Reguild

Greetings,
Bought an Eico 221 a couple weeks ago. It appears to be very accurate on DCV & Ohms. Haven't checked ACV yet. The set has held it's calibration well.
Of the 4 capacitors in the meter only the filter cap (2 uF) appears to be original. I plan to replace it with a Nichicon 10 uF 450 V Electrolytic. No need to change the others.
I plan to check all resistor values as there are quite a few 10% carbon composites as well as 2W composites. I don't know if they are original but I'm sure they have been there a while and are most likely out of spec. After all the meter is signed and dated '1951'. There are also a few 5% carbon resistors that look new. I'll replace them with 1% as well.
The DC & AC specs of the meter are 3% & 5% so the 1% resistors may be overkill, but I still like the idea.
I would like to gut the meter and replace all the resistors with 1% metal film. Perhaps the RNxxx type. These were used in the Sound Technology gear I have and are very stable over time.
I understand this meter is from 1951 and it's a piece of our hobbies history, but since new VTVMs are not available I would like to have this VTVM as accurate as possible for a long time of audio repairs both tube and solid state.
Any other resistor suggestions? I'm set on 1% Metal Films.

Last edited by jblmar; 23rd October 2013 at 11:53 AM.
  Reply With Quote
Old 23rd October 2013, 11:45 AM   #2
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
You would be well advised to use the original values and types.
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 23rd October 2013, 12:05 PM   #3
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
Thanks, Jon.
That's the type of answer I was fishing for since I'm new to VTVMs.
Since everything checks out O.K. I may just replace the original Filter Cap and check resistor values. The older ones I'll replace even if they measure within spec.
Do you advise cleaning the Pots with CRC QD Contact Cleaner or leave them alone as they appear to be good.
Keep sending your opinions.

Last edited by jblmar; 23rd October 2013 at 12:12 PM.
  Reply With Quote
Old 23rd October 2013, 12:12 PM   #4
DUG is online now DUG  Canada
diyAudio Member
 
Join Date: Jan 2003
Location: mississauga ontario canada
"If it is not broken, don't fix it."

__________________
Doug We are all learning...we can all help
"You can't stop the signal, Mal. Everything goes somewhere..."
  Reply With Quote
Old 23rd October 2013, 12:14 PM   #5
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
Quote:
Originally Posted by DUG View Post
"If it is not broken, don't fix it."

Agreed. I was trying to 'improve' it.
  Reply With Quote
Old 23rd October 2013, 12:24 PM   #6
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
Any opinions to the contrary?
  Reply With Quote
Old 23rd October 2013, 01:33 PM   #7
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
So the 1% Metal Film Resistor idea is out?
  Reply With Quote
Old 23rd October 2013, 03:40 PM   #8
jblmar is offline jblmar  United States
diyAudio Member
 
Join Date: Dec 2005
Location: Brooklyn, New York
Some history on this VTVM. I bought it from an AK member who lives down in Florida. Given the high humidity there, my guess is that moisture has caused most of the 60 year old resistors to drift. I'm not looking to play with the meter just to maintain it.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Eico 221 VTVM Probes jblmar Equipment & Tools 6 10th October 2013 10:31 PM
Ic 221-241 ?? rodolfo Solid State 8 2nd March 2013 07:38 AM
Eico NOS Mdl 232K VTVM Peak-to-Peak VTVM KIT UNOPENED HolySmokes Swap Meet 0 27th January 2012 10:01 PM
Danley TH-221 drawings ? matsj Subwoofers 37 23rd January 2012 10:04 PM
Eico 221 Voltmeter jdeitch11 Swap Meet 0 22nd February 2011 07:35 PM


New To Site? Need Help?

All times are GMT. The time now is 12:07 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2