UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Closed Thread
 
Thread Tools
Old 18th Mar 2023, 3:43 pm   #1
proton21
Triode
 
Join Date: Jun 2017
Location: Northampton, Northamptonshire, UK.
Posts: 28
Default Avo Mk IV Valve Tester

Hi, My trusty Avo MK IV has given up. As soon as I rotate the leakage control (on any setting) the meter shows about 5 Meg leakage, this happens even without any valve inserted. If you continue to test with a valve inserted, when you select "Test" for anode current the meter goes negative. Does anybody have a service manual or any ideas? Cheers, Pete.
proton21 is offline  
Old 18th Mar 2023, 6:33 pm   #2
trh01uk
Octode
 
trh01uk's Avatar
 
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,648
Default Re: Avo Mk IV Valve Tester

The working instructions are available at https://frank.pocnet.net/instruments..._Mk-IVuser.pdf

There are several experts on valve testers on this forum. I expect someone will have seen your fault before.


Richard
trh01uk is offline  
Old 18th Mar 2023, 6:42 pm   #3
trh01uk
Octode
 
trh01uk's Avatar
 
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,648
Default Re: Avo Mk IV Valve Tester

SOrry- just noticed you want the service instructions - not the working instructions. I do have the service manual, but at 15MB its four times too big to post on here.

What I can do is to provide a link to my copy so you can download it:

https://e.pcloud.link/publink/show?c...DmJcg6x8T09QuV


Richard
trh01uk is offline  
Old 18th Mar 2023, 6:53 pm   #4
trh01uk
Octode
 
trh01uk's Avatar
 
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,648
Default Re: Avo Mk IV Valve Tester

Incidentally, my guess about the leakage you are measuring is that it is caused by a leaky capacitor. I would make a start by replacing all the paper caps.


Richard
trh01uk is offline  
Old 18th Mar 2023, 8:07 pm   #5
Robert Gribnau
Heptode
 
Robert Gribnau's Avatar
 
Join Date: May 2017
Location: Konongo, Ghana
Posts: 510
Default Re: Avo Mk IV Valve Tester

The link to the service manual provided by Richard doesn't seem to work for me. This is a link to what I gathered on the AVO Mk IV valve tester, including the service manual:

https://drive.google.com/drive/folde...ycoeVwAJHgNMSj
__________________
Robert
Robert Gribnau is offline  
Old 19th Mar 2023, 1:59 pm   #6
trh01uk
Octode
 
trh01uk's Avatar
 
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,648
Default Re: Avo Mk IV Valve Tester

Quote:
Originally Posted by Robert Gribnau View Post
The link to the service manual provided by Richard doesn't seem to work for me. This is a link to what I gathered on the AVO Mk IV valve tester, including the service manual:

https://drive.google.com/drive/folde...ycoeVwAJHgNMSj

Sorry to provide a non-functioning link. I have just found the service manual with a file size within the forum's limits, so have attached it here in case its useful.


Richard
Attached Files
File Type: pdf VCM_Mk-IV_service.pdf (2.25 MB, 43 views)
trh01uk is offline  
Old 20th Mar 2023, 12:53 pm   #7
proton21
Triode
 
Join Date: Jun 2017
Location: Northampton, Northamptonshire, UK.
Posts: 28
Default Re: Avo Mk IV Valve Tester

Thanks everybody for your replies. I shall replace the caps first, then go from there.
proton21 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 2:41 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.