Turbo repair - The Nightmare Begins

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Richard Hull
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Turbo repair - The Nightmare Begins

Post by Richard Hull »

After two months of gathering parts and diagrams, I am finally ready to attack, with a vengeance, the repair of my turbo controller.

A thanks to Dan Knapp for the schematics and troubleshooting manual.

Sadly, it seems 6 IC's are no longer available, (discontinued) I hope one of these is not the problem.
Blessedly, all IC's are socketed!
I am making up the board jumpers that will allow the system to be spread out for easy access during repair and testing. I will give this my best shot in order to retain the pump for the "real" fusor V effort where there will be 0.000 arcing, by design. A fail here will have me drop the concept of a turbo pump in any future system and a return to the "plug and go" Leybold diff pump of fusor IV fame.

I include three photos of the work area and set up to attempt repair and testing. Wish me luck, I already have the skills, a bit of luck is always a plus.

Richard Hull
Attachments
Turbo repair (2).JPG
Turbo repair (3).JPG
Turbo repair (1).JPG
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
John Futter
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Re: Turbo repair - The Nightmare Begins

Post by John Futter »

Richard
Send me a list of the ics you need
I have quite an extensive pile of logic and analog leaded ics
Andrew Seltzman
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Re: Turbo repair - The Nightmare Begins

Post by Andrew Seltzman »

May be worth it to buy another controller, they're pretty cheap:

[url]https://www.ebay.com/itm/133173568909/url]
Andrew Seltzman
www.rtftechnologies.org
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Richard Hull
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Re: Turbo repair - The Nightmare Begins

Post by Richard Hull »

FIXED!!

Yes, the shotgun approach worked. I have spent the last two months and about $90 in orders from Jameco, Digi-key and Mouser ordering every IC in the turbo's controller system that was still made. DIPs (N package ICs of the 70s-80s) are going away fast! Fortunately, between the 3 suppliers, I found all the DIPs needed. Whew! Some, only offered in SOIC. There were about 5 ICs that were obsolete and no one had them. The controller used about 23 ICs over the 3 boards. While waiting for the IC's I checked all the transistors in-circuit and all were good. About 30 transistors were in the controller.

I have a stock, here, of about 3000 IC's Most are TTL and variants, CMOS, and a lot of linear. All from the 70's through the early 2000's. My stock yielded about 5 of the 15 ICs needed. Determined not to really trouble shoot until I shotgun blasted all the ICs I had accumulated into the 3 boards and give it a whirl.

It worked!! Now, which IC or ICs were defective?? Who cares? I have a working turbo again! I am pretty sure it was one of the many, CMOS, CD4000 series logic ICs that the discharge destroyed or the two odd ball SG3525 PWM chips in the power board electronics.

I loaded all the IC pulls in a bag and marked them "pulls TCP-40 ??" I also stuffed all the spare ICs I ordered, which are known good, into another bag marked NEW ICs for TCP-40. I put both of the bags, the four custom board jumpers, which I manufactured, and the Pfeiffer manual into a flip top box and marked it "TCP-40 Turbo ICs and manual". I put it with all my vacuum hoard up in the loft of the lab. Hopefully, I will never need that stuff again. ( ordered about 4 of each IC needed.)

I am glad I didn't have to troubleshoot as Pfeiffer put a lot of CMOS logic snaking all about the system to check for startup issues and feed or receive signals from about 8 op amps. Typical 70s electronics, but very serviceable as most of the parts are still floating around without any custom programmed ICs, thank goodness.

I ran the turbo in the old, soon to be dismantled, fusor V setup and it ran for 2 hours, no problems....

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Turbo repair - The Nightmare Begins

Post by Dennis P Brown »

Good idea - overwhelm the problem! Still, anyone with such a unit now knows who to buy required spare electric parts from.
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Richard Hull
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Re: Turbo repair - The Nightmare Begins

Post by Richard Hull »

It seems the nightmare began and ended in one day, once all the materials needed were amassed. This might be the shortest nightmare I have experienced on the tech front for a while. The time spent ferreting out the needed DIPs on the computer and on the phone, it turns out, was the real nightmare.

Now on to the real fusor V construction as I rip up the abortive first pass.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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