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-   -   Mullard HSVT (https://www.vintage-radio.net/forum/showthread.php?t=169748)

theredhouseinn 5th Aug 2020 5:03 pm

Mullard HSVT
 
A small problem.
I went to test a VP23 valve today, Guess what, No number 4 adaptor.
Can someone tell me what type of plug is on the adaptor, and the pin connections between the socket and plug?
With this info I can make one up.
John.

Horris 5th Aug 2020 7:50 pm

Re: Mullard HSVT
 
I will look it up for you tomorrow.
Dave

Ed_Dinning 5th Aug 2020 8:16 pm

Re: Mullard HSVT
 
Hi John, I think there are schematics in the huge thread on HSVT, they are easily made up and do come in useful.
Better do it while the bases are still available

Ed

Electronpusher0 6th Aug 2020 7:03 am

Re: Mullard HSVT
 
1 Attachment(s)
See the attached, from the /3 manual.

Peter

Electrical 6th Aug 2020 9:28 am

Re: Mullard HSVT
 
Hello John
The VP23 valve is a variable mu pentode with a MO (Mazda Octal) base. The Mullard HSVT has a MO socket, third from the left on the first row, socket number 10. According to my valve list you do not need an adaptor, only card number 207 and the valve plugged into socket 10.
Regards Stan.

frankmcvey 6th Aug 2020 10:07 am

Re: Mullard HSVT
 
My card chart (Dec '62) confirms Stan's suggestion re card 207 in the MO socket.

Cheers,

Frank

theredhouseinn 6th Aug 2020 12:21 pm

Re: Mullard HSVT
 
Thanks chaps.
Don't know what I would do without this forum.
john.

frankmcvey 6th Aug 2020 12:46 pm

Re: Mullard HSVT
 
2 Attachment(s)
... and just to close the circle, here's Adaptor No 4. As in Peter's attachment, the No 4 is indeed IO - UX5.

Cheers,

Frank

theredhouseinn 6th Aug 2020 4:07 pm

Re: Mullard HSVT
 
Hi chaps.
Sorry, age is begining to tell.
I had tested the vp23 and then picked up a 76, which is of course UX5 base.
I have a UX5 base on order so I can make an adaptor.

Another problem.
Does anyone have the pin designations for the cards 850 A & B
I am missing these cards in my kit.
It is for a 1V valve.
If I have the code I can make up new cards using gash duplicate cards. I blank off holes that are not used and punch out new ones in my jig.
John.

frankmcvey 6th Aug 2020 5:54 pm

Re: Mullard HSVT
 
Not a common card - I've just checked 3 sets and it wasn't present in any; nor is it present in PJL's MHSVT Calculator. Apparently when you ordered an HSVT, you got a standard suite of cards plus 100 cards of your own choosing; I'm guessing that it wasn't part of the standard suite.

Unless someone in the forum finds it, then probably your best bet is to email George, of Mullard Card Project fame. You'll find his email address near the top of this webpage. Or you can PM him - he goes under the handle of GMB on this forum.

I'd very much appreciate a copy of the layout when you get it, thanks.

Cheers,

Frank

GMB 7th Aug 2020 5:06 pm

Re: Mullard HSVT
 
Email me for those card layouts if you want to make your own.

theredhouseinn 8th Aug 2020 12:17 pm

Re: Mullard HSVT
 
Hi chaps.
I have just done a thorough check of my valve adaptors.
I am missing no. 3, small base for 807 is on it's way to me, so this will be solved soon.
I will then have adaptors 1 to 10, and 13.
Does anyone know what 11 & 12 are, and whether or not they were ever issued?
If they were issued, diagrams would be welcome if anyone has them.
John.

theredhouseinn 8th Aug 2020 2:22 pm

Re: Mullard HSVT
 
Hi chaps.
Just come across another problem, hope you can help me.
I need to test 4 Z759's. I have made a card number 1106, but I see a special adaptor is required for this valve test.
Does anyone have the details for constructing this adaptor?
John.

PJL 8th Aug 2020 3:06 pm

Re: Mullard HSVT
 
It uses non-standard short pins hence the need for a special socket.

Electrical 8th Aug 2020 4:22 pm

Re: Mullard HSVT
 
2 Attachment(s)
Hello John
Have a look at the data sheet for the GEC Z759 and Z359, both valves have a B9A base and are identical except for the heater ratings and the fact that the heater pins on the Z759 are pins 5 and 6, which is very unusual. The Z359 heater pins are the more conventional pins 4 and 5 and this valve does not need a special adaptor according to list number 8 and the valve table.
I do not have a copy of card 1106 for the Z759 but I do have card 928 for the Z359. I have attached a copy of card 928 and would be interested in the differences between the two cards and why the 6.3V 0.6A Z759 needs an adaptor and the 12.6V 0.3A Z359 does not.
Regards Stan.

theredhouseinn 8th Aug 2020 4:44 pm

Re: Mullard HSVT
 
Hi PJL.
The pins on my Z729's are the same length as any other B9A valve.
The card says that I have to use the IO base no2 on the tester.
So this special skt must be a IO plug with a B9A base on top.
John

frankmcvey 8th Aug 2020 5:52 pm

Re: Mullard HSVT
 
I'm a bit confused here, John! Is it info on the Z759 (post 13) or the Z729 (post 16) you need? Z729 is common enough, being equivalent to the EF86 and uses card 561.

As to your earlier question, I had a look through my sets of adaptors - no No11 or No12, although there are a number of unmarked adaptors. I can't find any mention of #11 or#12 in any of the manuals.

Cheers,

Frank

theredhouseinn 8th Aug 2020 8:27 pm

Re: Mullard HSVT
 
Sorry Frank.
The Z729 is a typo, it should read Z759.
John.

theredhouseinn 8th Aug 2020 8:45 pm

Re: Mullard HSVT
 
1 Attachment(s)
Hi Frank.
Copy of the card attached.
John.

theredhouseinn 21st Oct 2020 12:52 pm

Re: Mullard HSVT
 
Back on the problem of the special adaptor for the Z759 pentode.
I see from the base connections for the Z759 that the heater pins are 5 & 6, different from the usual 4 & 5 pins for a B9G base.
Putting in card 1106, with a IO plug in the IO socket, I get 6.8vac between pins 2 & 7, heater supply.
Pins 1,4, and 8 show a short to chassis, cathode and grid 3?
pin 3 has -1.95v to chassis, obviously the control grid supply.
Pins 5 & 6 both have 252vdc to chassis, anode and grid 2, but which is which?
The resistance between pins 5 & 6 is 220 ohms.
Any idea's chaps before I make up an adaptor.
I stand a 50 50 chance of getting the anode connection correct.
If it dosn't work I can always swap pins 5 & 6 round.
John.


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