uTracer 400V upgrade kit available...

If they glow, this is the place to be
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jack
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Post by jack » Sun Apr 26, 2015 9:47 pm

Paul Barker wrote:Doesn't look too difficult a conversion.
As I said, not too complex - just fiddly - my close-up vision is not great as I need a new presciption - piggy-backing the caps etc. was just awkward.

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Paul Barker
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Post by Paul Barker » Sun Apr 26, 2015 10:12 pm

Actually I take it back. Yes my close up focus is that of a 57 year old. Seriously handicapped compared to last time I soldered.
Got as far as the 100 ohm resistors and stopped for the night. It is very difficult.

Managed to replace all the transistors I needed to. If I remember right the cause of busting them a second time was after I had tested 813's. I'll just stick to testing more sane valves with my one in future.
I can do it right or I can do it now, but I can't do it right now.

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Post by jack » Mon Apr 27, 2015 10:20 am

I opted to do the resistor replacement rather than paralleling them in the end - it was far less work - less fiddly.

You do need decent wick - I've always use Chem-Wick which is without a doubt the best stuff around - cleans pads up like nothing else out there - not cheap, but very quick so pads don't lift.

http://www.ebay.co.uk/itm/251475610011

Clean off any flux etc. with IPA and a lint-free cloth - you'd never know the pad had been soldered...

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Paul Barker
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Post by Paul Barker » Mon Apr 27, 2015 9:37 pm

Thanks Nick, yes I agree the parallel method is very difficult. I did use it for the first resistor job because it's a small resistor packed in tight next to a larger resistor and a voltage reference diode. So I decided to parallel it was the best of two bad options. But I didn't manage it tight to the board as the pictures show. so I will need to make the board stand off a bit when I fix it back in.

Tonight no timetable do any of it.

I have ordered a different braid already. If I haven't finished by the time it comes I'll use it. but anyway, it will be good to have.
I can do it right or I can do it now, but I can't do it right now.

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Post by Paul Barker » Sun May 03, 2015 3:47 pm

Ok I was sent the two smal transistors and changed those with the conversion.

Sadly the bad channel which is the anode one is better but has a ceiling of 45 mA.

The screen has no ceiling so I have function using screen but connecting it to anode. Mostly I am only interested in triodes anyway.

With the 400v the compliance error becomes a problem.

In addition to these issues I have been a total wally and broken the heater supply in the unit. I put in a 6b4g and joined the cathode to one of the heater pins. It fried itself and the 6b4g. Costly.

However afterwards these two traces were measured with an external filament supply and the cathode joined to the zero volts of the filament dc supply. Therefore the bias numbers are shy -3v. Not of great significance.

I hope you lot have a less traumatic experience.

Image

Image
I can do it right or I can do it now, but I can't do it right now.

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Post by Paul Barker » Sun May 03, 2015 3:56 pm

My ineptitude asside, there are two matters standing in the way of excellence in the tracer concept. Both compounded by the new 400v facility.

1/ the inability to provide a bias voltage lower than -50v
2/ the compliance error

Though it remains a valuable tool. Perhaps best to gather the data with it and plot your own graph not showing the compliance error. Though the bias limitation is not fixable.

Having said that I am great full for what I do have and the 6b4g which survived my ignorance provides a linear plot.
I can do it right or I can do it now, but I can't do it right now.

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Post by jack » Sun May 03, 2015 5:03 pm

I seem to be getting on OK with mine, though I'm kind of paranoid about not detonating it :)

Just running through a bunch of tubes that I have in stock....

One nice trick is that you can test both sides of a double triode for equivalence at the same time - connect the grids together, use the screen as the second anode drive and select the appropriate plot - the uTracer will plot both simultaneously. Cool :thumbright:
Attachments
NIB JAN 6111WA Philips - Both Triodes.png
Both halves of a JAN 6111WA plotted on top of each other - one with solid lines, other with dashes...
NIB JAN 6111WA Philips.png
Philips JAN 6111WA sub-miniature double triode

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Post by Paul Barker » Sun May 03, 2015 6:15 pm

Yes the double triode matching is good. Thanks for the pointer.
By the way the fresh desoulder braid I ordered worked perfectly, though the task is still onerous.
I can do it right or I can do it now, but I can't do it right now.

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Post by thomas » Wed May 13, 2015 9:01 am

My u-tracer complete kit arrived today- ordered in a fit of enthusiasm on a rainy day- looks rather ummm involved….
Still I'll slowly plod along and build it by Autumn I'm sure!

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Post by jack » Wed May 13, 2015 9:35 am

thomas wrote:My u-tracer complete kit arrived today- ordered in a fit of enthusiasm on a rainy day- looks rather ummm involved
Still I'll slowly plod along and build it by Autumn I'm sure!
If you have any problems, let me know - just down the road and all that :)

The manual is excellent - he's sold about 500 of these world-wide, so the documentation is now very clear and precise with testing at every stage.

Key thing is to follow the manual religiously - don't jump around, and don't go onto the next stage until the previous one is complete and tested. All the SMDs are pre-soldered (except the inductors), the rest is normal through-hole stuff.

Its fun!

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Post by thomas » Wed May 13, 2015 10:39 am

Ta for that!

nickds1 wrote:
thomas wrote:My u-tracer complete kit arrived today- ordered in a fit of enthusiasm on a rainy day- looks rather ummm involved
Still I'll slowly plod along and build it by Autumn I'm sure!
If you have any problems, let me know - just down the road and all that :)

The manual is excellent - he's sold about 500 of these world-wide, so the documentation is now very clear and precise with testing at every stage.

Key thing is to follow the manual religiously - don't jump around, and don't go onto the next stage until the previous one is complete and tested. All the SMDs are pre-soldered (except the inductors), the rest is normal through-hole stuff.

Its fun!

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Re: uTracer 400V upgrade kit available...

Post by RhythMick » Fri Mar 09, 2018 11:29 pm

Slightly ashamed to admit I have a uTracer kit in my line of projects to build. I keep coming up with more interesting things to build and listen to!

Anyone in South Yorkshire building one? Might be fun to work side by side. Might mean I actually get it done.

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