25-03-2019, 05:58 PM
Cut pin 4 off the UL41 with a Dremel and still use the base as an anchor point.... Job done!
|
DAC90A Beginner
|
(25-03-2019, 03:21 PM)pwdrive Wrote: Maybe the pin 4 thing was good practice, remember that the UL41 valve was a relatively new kid on the block at that time and that it had a fairly high value of mutual conductance, the valve manufacturer recommended that a grid stopper when fitted should be connected as close to the valve as possible which to me implies that it should also be located as close to the valve as possible (which it was). It probably seemed the obvious thing to do at the time based on earlier practice regarding the use of the pin 6 of an octal valveholder. The difference, of course, was that in such cases, pin 6 of the valve was missing, which was not the case for pin 4 of the UL41! UPDATE I hadn't seen Trevor's 'solution' until after I'd posted that - it was completely coincidental!
25-03-2019, 06:33 PM
(25-03-2019, 05:58 PM)Murphyv310 Wrote: Cut pin 4 off the UL41 with a Dremel and still use the base as an anchor point.... Job done! I'm a little unhappy about this as it could stress the glass/metal seal. However if you've done it several times without trouble I'll be happier. Don't cut it off with side cutters as that will definitely stress the seal.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
25-03-2019, 06:41 PM
(25-03-2019, 06:17 PM)Terry Wrote: It probably seemed the obvious thing to do at the time based on earlier practice regarding the use of the pin 6 of an octal valveholder. The difference, of course, was that in such cases, pin 6 of the valve was missing, which was not the case for pin 4 of the UL41! Sometimes you have to be carful with octals, metalized valve in an R1155 receiver anyone.... Lawrence.
25-03-2019, 08:53 PM
(25-03-2019, 06:33 PM)ppppenguin Wrote:(25-03-2019, 05:58 PM)Murphyv310 Wrote: Cut pin 4 off the UL41 with a Dremel and still use the base as an anchor point.... Job done! Done a few over the years Jeffrey. As you rightly say side cutters are a no no. When I do it with the Dremel I do it in stages and hold the valve in foam rubber in a heavy glass jar for stability. A very fine nosed pliers are used at the pin right up at the glass to hold the valve at the pin and not the glass, a couple of goes with the fine cutting disc and all is well. Any I have done clear the connection in base with ease and I haven't had a failure of the seal..... yet!
02-04-2019, 12:22 PM
It has been a busy work fortnight, so no progress yet on my first DAC90A: but look what has arrived....
It was a lucky ebay bid, complete but assumed non-working, from which I may have salvaged the output transformer. Breaking a good set would have hurt, but the poor packaging and rough handling has removed any dilemma! The seller has refunded in full, so his misfortune is definitely my gain. The problem is, I can't resist a challenge, so I may try to epoxy the case back together and spray in some gaudy colour as I see others have done before. There's certainly nothing to lose. Then I'll be on the lookout for a transformer and a tuning scale. I can see how things might escalate.... Thanks again for all the helpful advice given in this thread.
02-04-2019, 12:43 PM
Go on, put it back together!
The dial is easy, all the various patterns are on file for download and printing onto waterslide paper is easy. Then apiece of glass or acrylic sheet and you have a tuning scale again. Superglue makes a good job of putting smashed cases back together, with a bit of re-enforcement inside as good as new. What colour ?
Boater Sam.
02-04-2019, 12:50 PM
Lemon yellow? Fuchsia pink ? There is something about the shape which invites such brashness. Thanks for your encouragement.
02-04-2019, 01:07 PM
Blue and yellow stripes
 Camo? Then try and find it!
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
02-04-2019, 06:40 PM
Hi, plenty of rewound transformers available and another forum member can do dial "transparencies".
Ed |
| Users browsing this thread: |
| 2 Guest(s) |