Mullard high speed valve tester cards - UK Vintage Radio Repair and Restoration Discussion Forum

simonmavity · 24th Aug 2017, 1:14 pm

Hi. I hope all is well. I am an untrained amp tech and have bought a high speed tester not realizing it needs cards to work. I read GMB has put together a database of cards. Any help would be nice. Thanks in advance.

Ed_Dinning · 24th Aug 2017, 9:02 pm

Hi Simon and welcome to the forum, you will find lots of data about the cards and how to make them(!) on the thread in the forum.
You may get lucky and find a set of cards on e-bay, but it is unlikely to be a full set and you probably would not want it anyway.
Your set should at least have the "mains", "HT" and "reject" cards to allow setting up.

While waiting for the cards you might like to check over the electronics, being valve operated it suffers from all the problems of leaky caps and resistors gone high.

Ed

frankmcvey · 24th Aug 2017, 11:43 pm

Hi, Simon.

HSVTs get neglected and die; the cards live forever. You'd think there would be hundreds of sets of orphaned cards available, but actually they don't come up very often and they're quite hard to come by. There is a set on Ebay at the moment with a wildly optimistic buy-it-now price of £569.

I have a jig for manufacturing cards and can help you out with the 3 test cards. Unfortunately, they wouldn't be freebies. The cards are made from 0.8 - 1.0mm SRBP sheet, which isn't cheap.

You'll be extremely lucky if the tester works properly straight out of the box - they usually require a lot of fettling, as Ed has pointed out. Unless the machine has been in recent use, at the very least the electrolytic caps will need reforming, so don't apply full mains - go through a lamp limiter.

If your machine is the Mark 4, it's relatively easy to work on. However the earlier marks weren't built with maintainability in mind, so the passives are a lot less accessible, and the style of solder tags used make component replacement much more difficult.

Fortunately there is plenty of documentation available for all 4 marks of the tester available on GMB's website here (bottom of the page)

Be aware as well that this is basically a green for good, red for bad and amber for ok-ish machine. It's not a characteristic tester, and it won't allow you to accurately match valves.

On the plus side, they're easy to use and pretty bulletproof once they're serviceable, with no delicate meters to fry if you get a switch or a pot wrong! And, as Ed says, as an amp tech you'll just be looking for a relatively small number of test cards for the more common audio valves and rectifiers.

Good luck with it, and PM me if you're interested in the test cards.

Cheers,

Frank

It might be a bit late for you now, but I wrote a brief blurb on buying HSVTs some time ago. It's here.

Station X · 27th Sep 2017, 12:38 pm

One post moved to a new thread here:-

http://www.vintage-radio.net/forum/s...d.php?t=140133

24th Aug 2017, 1:14 pm	#1
simonmavity Retired Dormant Member Join Date: Aug 2017 Location: Hull, East Yorkshire, UK. Posts: 1	Mullard high speed valve tester cards Hi. I hope all is well. I am an untrained amp tech and have bought a high speed tester not realizing it needs cards to work. I read GMB has put together a database of cards. Any help would be nice. Thanks in advance.

24th Aug 2017, 9:02 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Mullard high speed valve tester cards Hi Simon and welcome to the forum, you will find lots of data about the cards and how to make them(!) on the thread in the forum. You may get lucky and find a set of cards on e-bay, but it is unlikely to be a full set and you probably would not want it anyway. Your set should at least have the "mains", "HT" and "reject" cards to allow setting up. While waiting for the cards you might like to check over the electronics, being valve operated it suffers from all the problems of leaky caps and resistors gone high. Ed

24th Aug 2017, 11:43 pm	#3
frankmcvey Rest in Peace Join Date: Jan 2015 Location: Cottesmore, East Midlands, UK. Posts: 858	Re: Mullard high speed valve tester cards Hi, Simon. HSVTs get neglected and die; the cards live forever. You'd think there would be hundreds of sets of orphaned cards available, but actually they don't come up very often and they're quite hard to come by. There is a set on Ebay at the moment with a wildly optimistic buy-it-now price of £569. I have a jig for manufacturing cards and can help you out with the 3 test cards. Unfortunately, they wouldn't be freebies. The cards are made from 0.8 - 1.0mm SRBP sheet, which isn't cheap. You'll be extremely lucky if the tester works properly straight out of the box - they usually require a lot of fettling, as Ed has pointed out. Unless the machine has been in recent use, at the very least the electrolytic caps will need reforming, so don't apply full mains - go through a lamp limiter. If your machine is the Mark 4, it's relatively easy to work on. However the earlier marks weren't built with maintainability in mind, so the passives are a lot less accessible, and the style of solder tags used make component replacement much more difficult. Fortunately there is plenty of documentation available for all 4 marks of the tester available on GMB's website here (bottom of the page) Be aware as well that this is basically a green for good, red for bad and amber for ok-ish machine. It's not a characteristic tester, and it won't allow you to accurately match valves. On the plus side, they're easy to use and pretty bulletproof once they're serviceable, with no delicate meters to fry if you get a switch or a pot wrong! And, as Ed says, as an amp tech you'll just be looking for a relatively small number of test cards for the more common audio valves and rectifiers. Good luck with it, and PM me if you're interested in the test cards. Cheers, Frank It might be a bit late for you now, but I wrote a brief blurb on buying HSVTs some time ago. It's here. Last edited by frankmcvey; 25th Aug 2017 at 12:07 am.

27th Sep 2017, 12:38 pm	#4
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Mullard high speed valve tester cards One post moved to a new thread here:- http://www.vintage-radio.net/forum/s...d.php?t=140133 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.