Tek 4051 semi-repaired

Brad H vintagecomputer at bettercomputing.net
Wed Oct 4 01:10:35 CDT 2017


    
That would be awesome, as long as you aren't putting yourself out.  Any information I can give this guy helps.  He is a real wizard and has fixed machines in my collection that haven't worked in eons.  But he usually needs some kind of referene on what he should be seeing to figure out what is wrong.
Many thanks if you can do it.
Brad


Sent from my Samsung device

-------- Original message --------
From: Randy Dawson <rdawson16 at hotmail.com> 
Date: 2017-10-03  8:01 PM  (GMT-08:00) 
To: 'Pete Lancashire' <pete at petelancashire.com>, Brad H <vintagecomputer at bettercomputing.net>, "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> 
Subject: Re: Tek 4051 semi-repaired 



I will be glad to open mine up, and 'PhotoFact' it for you.



I can take scope shots of the critical signals, voltage rails.  I suppose the first, would be if you hit the HOME PAGE key it should clear the screen, I can follow that signal path, and take some scope shots...



Even with the screen flooded,if I let it sit and hit space, not HOME PAGE on my working 4051, you can still see the characters you type faintly, and the cursor blink.






Randy









From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Brad H via cctalk <cctalk at classiccmp.org>

Sent: Tuesday, October 3, 2017 7:10 PM

To: 'Pete Lancashire'; 'General Discussion: On-Topic and Off-Topic Posts'

Subject: RE: Tek 4051 semi-repaired
 



I’ll have to check that when I get it back – I didn’t really have a look inside and wouldn’t have known to look for that.  I’m hoping not.. cosmetically the machine is excellent – the interior could almost fool you into thinking you were
 looking into a brand new Mac, with all that stainless.  But that doesn’t mean anything in terms of the actual components, of course.



 



My CRT guy seems to be convinced the computer isn’t doing what it should be, based on his read of the schematics.  But he said the only way he could be really sure was to have a working unit to compare to.



 



From: xyzzypdx at gmail.com [mailto:xyzzypdx at gmail.com] On Behalf Of Pete Lancashire

Sent: Tuesday, October 3, 2017 10:01 AM

To: Brad H <vintagecomputer at bettercomputing.net>; General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>

Cc: Ian Finder <ian.finder at gmail.com>

Subject: Re: Tek 4051 semi-repaired



 



If the CRT floods one can say the CRT is good with one major thing left, phosphor burns. In a DVST (Direct View Storage Tube) the most common effect is the burn area will not store with the same potential as the rest of the tube, or if burned enough will not
 store at all. There are other things that can go wrong but so far you know the flood guns are  good, do you see the man CRT gun assemblies filament light up (can't remember if can been seen with the shield on) ?



 



Good Luck, while at Tek I kept thinking of building one but never did.



 



-pete



 



On Tue, Oct 3, 2017 at 9:42 AM, Brad H via cctalk <cctalk at classiccmp.org <mailto:cctalk at classiccmp.org> > wrote:



Also the computer itself *was* semi-working.. with the monitor board disconnected, voltages were good and I could blindly type in a simple endless loop program and get the ‘BUSY’ light to light up when I ran it.







I don’t have the computer just yet and my tech guy didn’t have time to try entering something like that.  So I’ll have to confirm.  He seems to think three indicator lights on the right come up on power on now and then go out.  The power light at the bottom
 appears to be dead.







From: Ian Finder [mailto:ian.finder at gmail.com <mailto:ian.finder at gmail.com> ]

Sent: Tuesday, October 3, 2017 9:39 AM

To: Brad H <vintagecomputer at bettercomputing.net <mailto:vintagecomputer at bettercomputing.net> >; General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>
 >

Subject: Re: Tek 4051 semi-repaired







Does it warm up or flood?







"When I got my 4051, on power up there



would be no voltage to the motherboard and nothing came up on the screen.

That has been fixed, however we still do not have any kind of prompt or

anything appearing."





Care to share with the class what you've done so far?







On Tue, Oct 3, 2017 at 9:29 AM, Brad H via cctalk <cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>  <mailto:cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>
 > > wrote:



Hi there,







My go-to guy for CRT stuff has informed me that he has the CRT on my 4051

working and that the tube is good.  When I got my 4051, on power up there

would be no voltage to the motherboard and nothing came up on the screen.

That has been fixed, however we still do not have any kind of prompt or

anything appearing.







Wondering if anyone has any ideas on where to go from here?   I'm picking up

the machine this week and will do some more testing.. hopefully the board

didn't take any damage while he was working on the CRT.







Brad















--



   Ian Finder

   (206) 395-MIPS



   ian.finder at gmail.com <mailto:ian.finder at gmail.com>  <mailto:ian.finder at gmail.com <mailto:ian.finder at gmail.com> >









 <http://www.avg.com/email-signature?utm_medium=email <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
 &utm_source=link&utm_campaign=sig-email&utm_content=emailclient>



Virus-free.  <http://www.avg.com/email-signature?utm_medium=email <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
 &utm_source=link&utm_campaign=sig-email&utm_content=emailclient> 
www.avg.com <http://www.avg.com> 











 



 





 <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>




Virus-free.  <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
www.avg.com 



 








More information about the cctalk mailing list