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plumbweiss 15th Nov 2006 10:29 pm

Re: Mullard Valve Tester Card Project
There are people around who make shellac-coated books for playing fairground organs. They generally have a foot-operated punch and use a folded thick card which is sprayed or painted with shellac after punching to make them hard, as the organ keys are strongly spring loaded fingers and the cards have to be repeatedly played without wear. Maybe worth aproaching them ? And how about fitting the HST with a socket for an interface to a digital relay output card from a PC? You could link this to a valve database and Im sure it could be done discreetly? They do this with fair organs too!!

GMB 20th Dec 2006 10:48 pm

Re: Mullard Valve Tester Card Project
I had hoped to be able to publish the results by now but I am still waiting for a number of people who have indicated that they should be able to make a useful contribution but haven't quite got round to it. Hopefully they will find the time over the Christmas break. ;)

While we are waiting I thought you might be interested in a few manuals and circuits that have been donated. Many thanks to everyone who has helped with this.

The various models of the E7600 all work in the same way but there have been a number of circuit variants implementing the same functionality. I think the manual of the military version (CT80) has the best description of how the tester actually works.

Also, the circuit diagram has been drafted in some very different styles so I put all the circuits I have found into one document.

You can find all this on my web site at

Merry Christmas!!

ecc83 7th Apr 2007 8:09 pm

Re: Mullard Valve Tester Card Project
I well remember being the "test jockey" as an apprentice. Prob' a stupid suggestion but since it is now possible to model electronic circuits on a pc can the testers circuit not be so modelled and then the "mission impossible" card situation avoided?

GMB 7th Apr 2007 8:23 pm

Re: Mullard Valve Tester Card Project
PJL has somewhat done this and so we are hoping be able to publish the database with interpretation of the card.

However, modelling fatal situations not simply a case of modelling the tester itself as unexpected interactions with the valve can also be an issue.

PJL 8th Apr 2007 2:55 pm

Re: Mullard Valve Tester Card Project
Just to clarify, the effort has focused on calculating the test conditions from which an approximate 'real' value can be extrapolated from the deflection. I have personally found it invaluable.

Although some error checking is performed it is by no means exhaustive. It does allow modelling of custom cards but could only be used to verify your own design. Certain changes can be made with the card fairly easily and if there is sufficient interest I will document how to do this.

GMB 2nd Dec 2007 11:57 pm

Re: Mullard Valve Tester Card Project
Just when it seemed that things were slowing down another 100+ new cards turned up at Wootton Basssett. This has pushed the list of missing cards close to extinction and I am still awaiting a few more. There is now a real possibility to bag the entire lot.

So if anyone has missed this project, please look at the current state of play at and see if you have the last few cards.

(...and yes, this project has proved to be a lot more work than I had anticipated).

Electrical 28th Nov 2008 4:12 pm

Re: Mullard Valve Tester Card Project
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Hello everyone, I have read all the posts on this topic with interest, as I too have been collecting sets of cards in order to build up a complete set of cards. I originally found GMB’s Mullard Tester Card Project by searching on Google about 18 months ago and sent off all the copies of the missing cards I had via email.
In one of the posts it was mentioned about rouge cards and I wondered if anyone had come across cards that have been miss punched as In the example of card Diode Test 1B, (AC/HLDD) where the holes are miss registered by approximately, 5mm, as shown in attached picture. In this case, the tester did nothing, as all the contacts in the gate switch were, held open, with the tester indicating an open circuit heater. Since I found this card, I always check to see if the holes are all in the correct place. I think you could imagine what would happen if the holes had been another 3mm miss registered, the set HT holes row ‘L’ would select the mains transformer secondary taps and would short together, with out any secondary fuses the mains transformer would have little protection and would probably burn out before you realised what had happened.
With reference to the card material, the original cards appear to be, made from 0.6mm (25thou) ‘Tufnol’, which in the ‘Kite Brand’ form has a very high electric strength. It is a Phenolic paper laminate, SRBP (Synthetic Resin Bonded Paper) and is available to order in 4 foot square sheets 0.6mm thick, or 0.8mm thick, off the shelf. I have made blank cards from 0.8mm Kite Brand Tufnol and punched them on my jig, and have all worked very well. I cut the cards to an approximate size and a friend of mine milled the cards to the finished size of 8.25” X 5”, with the 1.5” notch in the side. At present, I have built up a supply of hundreds of blank cards, made from acquired scraps of 0.8mm Tufnol sheet, all I need now is copies of my missing cards to punch new ones to complete the set. My punch jig has a slide fitted on the top to allow me to copy a card by using the sample card as a template to reduce errors when punching.
One member suggested fitting a digital relay card to a tester and controlling it from a PC, well this may be another one of my follies but I have already built an interface consisting of 130 single pole relays, in 13 rows of 10 columns. Each relay coil is, switched via a transistor with a 15k resistor in its base and a suppression diode across the relay, operating coil. Please see picture. The interface is built, up from 13 separate PCB’s, with links fitted across the rows from A to M and the columns are linked across the top terminal blocks. As you can see it is not finished, yet and at present I am working on a diode matrix card consisting of 130 X 3.5mm jack sockets to program and test the relays. The matrix is fitted with a jig to slide a standard card in and by inserting a 3.5mm plug with a diode wired across the terminals, through each hole in the card will energise the appropriate relay and I hope will give the correct settings for the valve tester. Using this method of programming, a card for an unlisted type of valve could be set up by varying the positions of the diode plugs in the anode voltage set row ‘L’ and the grid bias row ‘I’ until the correct conditions have been achieved. To check these conditions I have built yet another jig, which consists of an octal plug and socket joined, together with 1 ohm resistor in series with the anode, screen and cathode pins, with pairs of wires across each resistor, which will indicate the current on a mili-volt range of a digital voltmeter. The anode and screen voltages are, measured with respect to the cathode, which on the tester is usually earthy. I did bring the grid connection out as well, but connecting a 10 mega ohm impedance digital voltmeter between the grid and the earthy cathode causes the spot on the tester to drop down to just about half way and there are signs of instability in the spot. I did intend to build in three small digital voltmeters into the tester to measure the parameters as each type of valve is tested, both voltage and current, but I will have to increase the input impedance of the grid circuit voltmeter first.
I do hope this post in not too long or not applicable to the original.

Regards Stan.

Ed_Dinning 28th Nov 2008 8:55 pm

Re: Mullard Valve Tester Card Project
Hi Stan, PM me if you need any prints of cards you do not have as I have about an 80% collection of cards and I'm in the area (I live near Stanley).

I'ts also worth fitting fuses in all the HT feeds from the transformer as it is a very complex beast that would be impossible to replicate. (I did one for the AVO 2 panel tester and that was very hard work).

Glad to se the project being revived again.


Electrical 28th Nov 2008 10:24 pm

Re: Mullard Valve Tester Card Project
Hi Ed, thanks for the offer, over the years I have collected 5 boxes of cards and at present I am short of about 215 cards. I checked this against my January 1966 Test Card Index list so I am sure there will be a few, more modern ones missing, as I am sure there must be a more modern list out there. I know the interface looks a bit big and cumbersome at present but at present I would like to see if the principal will work, that’s why I transistorised the relays so that if I ever get around to building a computer interface and find a way to multiplex all 130 relays the drivers are already there. When I connect it all up to a tester I feel sure there may be instability problems to solve first as I found when I built a jig to measure octal audio valves and applied a digital voltmeter to the grid. This is the reason I decided to make a simple diode matrix plug board to do the testing as I could end up with more faults in the computer programming and multiplexing, making it even harder to sort out. When it is complete and working, I will design a single PCB, with all the relays on an only use 400-volt 16A relays in the mains and HT rows. I am sure smaller 250 volt 7A PCB relays could be used in the base selection, so the size could be reduced considerably, also ULN2003 IC drivers instead of the resistor, transistor and diode drivers.
Dare I ask how far the complete list is off completion?
Regards Stan.

dave walsh 28th Nov 2008 11:24 pm

Re: Mullard Valve Tester Card Project
Hi all! Further to my post *34 [way back in 2006] sadly I have not done much to advance the cause since then. Are there any really rare cards in that list I wonder?
It's possible that I may sell of my Mk 6 at some point in the near future [in the correct section of course mods] as it's a bit like me having top flight guitar and not actually playing very much, or very well:-]!
If my cards were actually needed for a master index/resource available to others, I would want the tester to go to someone interested in co-operating with people like Ed or GMB and their projects.
I find that their is a lot of satisfaction in helping people to fill gaps with a particular interest even if you're not at the same level of competence.
Dave W

humphrey 29th Nov 2008 8:17 am

Re: Mullard Valve Tester Card Project
Is it possible to make a card if the valve data is available?

Ed_Dinning 29th Nov 2008 8:42 pm

Re: Mullard Valve Tester Card Project
HI Humphrey, in theory , yes.
In practice the holes to connect the supplies to the correct base pins is easy, as is the selection of heater voltages.
The difficult bit comes with the electrode voltages and the pass/fail limits. This is because the valve is not always tested at the voltage and current levels shown in valve data.
There may be some more theory on this in previous threads.


PJL 23rd Dec 2008 9:37 am

Re: Mullard Valve Tester Card Project
The emulator I have produced would help with this but you would be best starting from a card for a valve with the same pinouts...Peter

humphrey 2nd Aug 2009 8:26 am

Re: Mullard Valve Tester Card Project
I have scanned a valve test report sheet here

voodoo audio 9th Sep 2009 2:14 pm

Re: Mullard Valve Tester Card Project
4 Attachment(s)

Originally Posted by GMB (Post 52900)
Ed has sent me this picture of the pre-war Mullard tester, has anyone got a better picture (or even has an actual tester)?

Here is one picture have a few more of the tester and wooden box with lower draw full of adapters

voodoo audio 9th Sep 2009 2:22 pm

Re: Mullard Valve Tester Card Project
1 Attachment(s)

Originally Posted by humphrey (Post 214591)
Is it possible to make a card if the valve data is available?

Hope to share the info i have here with the tester in my shack ,here is card i just found with some nice details on it .

GMB 9th Sep 2009 9:25 pm

Re: Mullard Valve Tester Card Project
Just to clarify, the above device is the Mullard Master Test Board which is Mullard's version of the Philips "Cartomatic". It had a rather short production run due to the war and is quite unlike the MHSVT so it's cards do not relate to the E7600.

But it isn't the oldest of these testers. The Philips P.S.T.T predates it slightly, but the MTB is rather more useful, being a lot more than just a valve tester.

Anyone interested in it can find a manual for it on my web site.

GMB 31st Mar 2010 10:09 am

Re: Mullard Valve Tester Card Project
UPDATE: Just 5 card sets known to exist that are not found. Total of 7 cards.

This is so close!

So if you haven't checked yet then please see if you have 916, 917, 1027ABC, 1080 or 1138.

dave walsh 31st Mar 2010 1:31 pm

Re: Mullard Valve Tester Card Project
Hi George. Further to post 50* here I've checked my 23/2/06 list again and it's showing 916/917 so that could-perhaps- be two less jigsaw pieces for your determined project, unless there is crucial damage or they are some obscure derivative of the original. Unfortunately, a family situation is likely to keep me in the south for several weeks but I will be happy to check things out when I get back. It doesn't look like I can help with the others though I'm afraid.
I'm probaly getting close to selling off my tester now as it is hardly in constant useo [or at all] so it doesn't really justify my hanging on to it when someone else could get a better outcome. Cheers Dave W Bexhill

humphrey 4th Apr 2010 11:23 am

Re: Mullard Valve Tester Card Project
I have 916 if you still need it.

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