Mullard E7600/4 tube tester card database

[Roland Huisman]

Hello! I could not resist buying this old Mullard E7600/4.
I think the tester is a restoration project, DG7-5 is missing... So what more?
This week the tester will come here together with a box of cards.

I wonder, a friend of mine has a Mullard CT80, are the cards the same?

And is there some sort of database with these cards already? There are
probably some newer tubes which I would like to test on it as well...

Regards, Roland

[Cobaltblue]

Hi Roland

This thread may be of interest.

https://www.vintage-radio.net/forum/...ead.php?t=6112

Cheers

Mike T

[Roland Huisman]

Thanks, I found that one but initially I found a lot of dead links. But in the later pages there are very useful links. So I will go from there, very curious... So thanks for pointing me there. I will update this topic if anyone thinks it is interesting to see my tester being restored. Maybe I have some questions too. We will see.

Thanks, Roland

[Roland Huisman]

I also found this tool on this website. But it seems to be very old and java script is not supported any more I think... Any new versions from this tool? I can't reply in that topic any more...

https://www.vintage-radio.net/forum/...9&postcount=13

[GMB]

Mullard CT80, are the cards the same?

YES - all that is different is the annotation on the cards.

Avoid the (escaped) javascript tool as it contains erroneous data.

If you need specific cards I can probably provide the details for making it.
One day I hope to finish and verify the whiole database that I have collected so far.

[Roland Huisman]

Well I got it running under IE with some warnings. But thanks for letting me know about possible errors. So I should not use that tool? At the moment I'm not really searching for specific cards. I need to restore the tester first.

The tester arrived today! Needs some TLC as usual with this old stuff... Most components and tubes are dated in 1966, and some capacitors even 1969. So I think this is a late tester...

The only parts that I'm missing is the CRT and its holder... I hope to find some sort of old oscilloscope, or does someone have such a CRT holder for sale?

Originally Posted by GMB

One day I hope to finish and verify the whiole database that I have collected so far.

Well I was hoping to find a document with all cards in it. I have about 1000 cards with this machine. So I have to check if I have cards that are still missing in your database... Any up to date list about that?

Regards, Roland

[Electronpusher0]

I have a spare CRT, I'm pretty sure I also have the housing, you can have foc (just the cost of postage).
I converted mine to use a bargraph display.

https://www.vintage-radio.net/forum/...d.php?t=172215

PM me with your address.

Peter

[Ed_Dinning]

Hi Roland, looks like a good find and quite clean.
I gave mine a good service a year or so ago and it is performing much better now as many of the components were out of spec.
I may have a spare tube for the tester, but no mountings I'm afraid, so call me if you have no success in getting one elsewhere.
I can probably deliver the tube if needed as I will be travelling to Austria via Europort in early Sept

I have a good collection of cards but also made up the card punch described in the thread to make cards that I do not have. The various adapters detailed in the instructions are also worth making up.
It is also worthwhile fitting a bank of fuses on all the HT outputs from the transformer as it is quite special and I would not want to attempt to rewind it

Cheers, Ed

[GMB]

Any up to date list about that?

My web site is up to date. http://air-ministry.uk/mullard.htm
Although I have received quite a few contributions since the fairly old dates you will see there, nothing new has actually turned up. It is hard to know what the most up to date versions are for the various cards and a few cards remain to be found.

[Maarten]

@Electronpusher0: your display looks really good, as if Mullard had intended to use such a display all along.

You write about the EL37 being obsolete by 1954, but strangely Roland's tester which seems to be a very late production one, is actually fitted with an EL37, though there's no small print on it so it might have been imported/rebranded. Date codes on other valves range from 1964-1966, capacitors 1966-1969. They don't look as if they've been replaced.

[Roland Huisman]

@ Peter, Great! Already sent you a PM.

@ Ed, Peter has probably a tube and probably its housing too. Good idea to add some fuses to the tester. I wonder if I need some of these adapters. I have some magnoval tubes. I have just two compactron tubes known to be good. These are quite nasty to test on a tester like this I think.

@ GMB, you have a nice site. You said that the javascript tool is not 100% sure to be right? Is there a complete database for the cards available? I have seen some cards, but it would be great to have all the card information available.

I've checked your missing cards, but I don't have them either...

@ Maarten, yes I've sent you many pictures trough whatsapp while inspecting the tester. Really surprising to see that the components are dated in the late sixties...


A few other questions... What kind of mains plug do I need for this tester? I've never seen this. Looks like some sort of Bulgin plug. (on this site plug 1 and 2)

And is there a horizontal PDF scan/document like the original manual which is in the back of the tester? Mine is gone... And does anyone have a reference for the transparent plastic with the lines in front of the CRT. That is also missing...

See pictures which I got from this youtube video...

Regards, Roland

[Electronpusher0]

re the crt scale, I don't know if this is any help, also a picture of mine before I changed the display.

Peter

[Roland Huisman]

Hi Peter, thanks! I will see if I can make something like that.

In addition to my previous questions, does anyone have a close-up from the transformer connections? The big transformer has one loose wire and some solder joints seem to be soldered on.

It would be nice if I can compare it with another tester.

Regards, Roland

[Roland Huisman]

In the meanwhile I found a mains plug through a Dutch forum

I've replaced the four 16uF electrolytic caps and the wax capacitor. Resistor values seem to be quite good. Only the carbon composite resistors are a bit out of range which we can expect nowadays...

Checked the tubes as well. They are testing fine, but one EF91 is a bit worn. Maybe I have a spare from my Bush TV22F project...

Regards, Roland

[TowerRadio]

I had to replace the 4.00 mfd 500v electrolytics for the eht to the crt,I used film ones,4.7mfd. 630v. The focus was useless,after changing electrolytics it was fine.Les

[stevehertz]

Back in the 70s, at Harpendon I got to know a chap called Don Hewlett who worked at Mullard servicing the valve testers. I think he headed up the department. He was a minefield of information on them, a gent and a great help to me. One thing he told me was to set up the pass and fail limits differently to how the manual says. I can't recall the procedure offhand, but I'll dig it out and post here. Just for now though, he told me this quick way to ID a tester by the shape of the carrying handles. You may notice there's no mk2. Don said there wasn't one.

[stevehertz]

Originally Posted by TowerRadio

I had to replace the 4.00 mfd 500v electrolytics for the eht to the crt,I used film ones,4.7mfd. 630v. The focus was useless,after changing electrolytics it was fine.Les

I was getting a comet shaped dot using something like 4uf at only 400V (I can't recall the exact values, but the voltage was too low). I then changed to using two 8uf 400v in series and all was fine. Don (see post above) told me that fix for the comet shaped dot.

[Electronpusher0]

I have now found the CRT and housing!

We were moving house and everything was packed up, anyway I have found it now.
I have PMed Roland and will post it.

Peter

[Roland Huisman]

Oh great, including the housing! This will speed up the restoration from the tester. Thanks a lot!

Regards, Roland

[Roland Huisman]

Originally Posted by TowerRadio

I had to replace the 4.00 mfd 500v electrolytics for the eht to the crt,I used film ones,4.7mfd. 630v. The focus was useless,after changing electrolytics it was fine.Les

Yes I have to check these two too. I'm afraid that these are bad too...

@stevehertz
Fun to see how these testers evolved. A friend of mine has a CT80 with a countless amount of CV cards. If we have some spare time we want to scan all the cards we have and drop it in a PDF file or something like that. Together we have about 2000+ cards I think... I have some cards that he want and vice versa...

Regards, Roland