Testing the TK Tar Baby

[picowatt]

On the nerd side of things, I know TK plays around with PCs and makes Ubuntu boxes and stuff like that.

Well, I am finishing off building an AMD 3.6 GHz 8-core (count 'em) 16-gig-RAM monster computer!  OMG, what a machine!  USB 3.0, SATA3!  Sorry, TK, but it's running Win7 64-bit.

I haven't built a computer in about three years, which is a long time in computer time.  You will be able to run 10 applications at the same time including all sorts of Flash games and other crap and this computer should slice though it all like a white hot knife through butter!

It's so damn fast that I am assuming that after about six months the computer will not get sluggish.  The software itself will get sluggish, but you won't perceive it because the computer is so damn fast!

It's been running Prime95 for 12 hours without a hiccup.  It's a build for a friend and I am not bothering to overclock it.  There is no point.  It's whisper quiet under normal operation.

Okay, back to the never ending story.

MileHigh

MH,

What MB, case, fans, etc. did you use?

PW

[picowatt]

TK,

Do you know what the output supplies are in the F43?  I am assuming that they are close to +/- 40 volts or so.  If so, the MPSU's were being pushed a bit hard regarding their V rating.  I would consider the 2SD669/2SB649 pairs I mentioned.  They have a higher V rating (the A versions even moreso).  Likely it was the V rating of the MPSU's that got you in to trouble in the first place.  Even though the 2S parts are only 1.5 amp devices, they will likely suffice.  Even with a full 40 volt offset at DC (I think you said it would do +/- 40 volts) into 50 ohms and with a little bias, you would still be under an amp.

Look at the board and trace from the 50R output.  See if you can find a couple diodes going from the amp side of the 50R trace to the rails.  If you cannot find them, I would consider adding them.  These would protect the output section from overvoltage by dumping any voltage in excess of the output supply to the rails.  I would to use a pair of fast 3 amp diodes with a PRV of 600 volts or so.

What does the unit have for the 50R?

Let me know how it's going.

PW

 

[TinselKoala]

@PW:
Well, my supplier didn't have any of the plausible subs for the MPSU06 and 56 transistors. He did list the NTE189 as available... for THIRTY DOLLARS !! But the NTE188 is discontinued and not available from him.

He did have the NTE 128 and 129 pair in stock but I think my present ones are probably still good... but I bought some new ones anyway.
And I got some fuses.... a .375 A slowblow is over two dollars, now... I am flabbergasted.
So I'm down to ordering from the internet.

(The "new" RA blog will be the same old same old, after a while. But this time....there is a history available, in my scope shots compendium and my collection of pertinent blog and forum posts. The wonderful thing is that all of it is in her own words, and her own data. No TK spin possible, just the facts from the horse's mouth!! And it's all publicly available for anyone with a computer.)

I just ordered 2 MPSU56 and 2 MPSU05 (not 06) from Utsource.net for 18 dollars plus 4 dollars shipping... I think. They are supposed to email me with details.
I also see some on EBay, MPSU06 for around 7-9 dollars each depending on source, and the same for MPSU56. So they are out there. Still... it would be nice to find some cheaper substitutes for testing purposes.

[picowatt]

@PW:
Well, my supplier didn't have any of the plausible subs for the MPSU06 and 56 transistors. He did list the NTE189 as available... for THIRTY DOLLARS !! But the NTE188 is discontinued and not available from him.

He did have the NTE 128 and 129 pair in stock but I think my present ones are probably still good... but I bought some new ones anyway.
And I got some fuses.... a .375 A slowblow is over two dollars, now... I am flabbergasted.
So I'm down to ordering from the internet.

(The "new" RA blog will be the same old same old, after a while. But this time....there is a history available, in my scope shots compendium and my collection of pertinent blog and forum posts. The wonderful thing is that all of it is in her own words, and her own data. No TK spin possible, just the facts from the horse's mouth!! And it's all publicly available for anyone with a computer.)

I just ordered 2 MPSU56 and 2 MPSU05 (not 06) from Utsource.net for 18 dollars plus 4 dollars shipping... I think. They are supposed to email me with details.
I also see some on EBay, MPSU06 for around 7-9 dollars each depending on source, and the same for MPSU56. So they are out there. Still... it would be nice to find some cheaper substitutes for testing purposes.

TK,

I would not use the MPSU05.  I believe it is only a 60 volt device compared to the '06 which was an 80 volt device.

I'll bet that IEC would have used a higer voltage device if a fast enough one could be found in the F43's day.

If the output supplies are +/- 40 volts or so, you will need a minimum of an 80 volt device.

PW

[picowatt]

TK,

Looks like the '06 and '56 is available on ebay for 8-10 dollars each... ouch!

Have you checked with your surplus stores?

PW