[Heath] HO 10 scope question (Update)

[James Owen]

Hi Mike,
   Before you go to too much trouble let's trouble shoot a little. When you finally get a trace is it centered with the vertical and horizontal position controls near center. Since you said the high value resistors are very high, I suspect that the trace is off scale when cold. As  the resistors warm up (carbon resistors decrease in resistance as they warm) the trace then drifts into view. Replace the high value resistors in the position and focus circuits before you do much more and see what happend.

 73 Jim

James C. Owen, III K4CGY


________________________________
From: K5MLC (Mike) <k5mlc at sbcglobal.net>
To: "mdilli at nnwifi.com" <mdilli at nnwifi.com>
Cc: "heath at puck.nether.net" <heath at puck.nether.net>
Sent: Wednesday, July 13, 2011 12:34 PM
Subject: Re: [Heath] HO 10 scope question (Update)


Thanks, Morris.  Actually, yes, I remember waiting on the CRT and the other tubes to warm up in the old B&W sets! LOL.  I'd forgotten about that experience. Age here is 57. Guess it is time to bring out the old tube testor and start checking all the tubes before I start ordering stuff.  Thanks again for the shock to the gray matter ~ reminding me about the "extended" wait time. :)  Mike 



From: Morris <mdilli at nnwifi.com>
>To: 'K5MLC (Mike)' <k5mlc at sbcglobal.net>
>Cc: w4gbw at bellsouth.net; cemilton at aol.com; heath at puck.nether.net
>Sent: Tuesday, July 12, 2011 5:28 PM
>Subject: RE: [Heath] HO 10 scope question (Update)
>
>
>You must be too young to remember waiting on the defective CRT on the old black and white TV to warm up so we could see a picture.   Sounds like the CRT is the problem with reduced emission or a cathode short.  There was available a special filament voltage booster that sometimes extended the life of the old CRT but it was marginal in value IIRC.
> 
> 
>Morris 
>-----Original Message-----
>>From: heath-bounces at puck.nether.net [mailto:heath-bounces at puck.nether.net] On Behalf Of K5MLC (Mike)
>>Sent: Tuesday, July 12, 2011 10:29 AM
>>To: cemilton at aol.com; w4gbw at bellsouth.net; heath at puck.nether.net
>>Subject: Re: [Heath] HO 10 scope question (Update)
>>
>>
>>Hello everyone,
>> 
>>Thanks for all the great ideas! Here is an update on the HO 10 scope project: I opened her up and gave her a good look over, looking for obvious burned stuff, loose stuff, etc. I unplugged the tubes and did a visual on those, and returned them to their sockets. I measured the caps and resistors and found nothing "way out," although several of the hv resistors are higher in value and are on the "replace" list. I found nothing obviously damaged, so I plugged her in and switched her on, again watching for anything unusual.  The tubes lit up. I waited, but no trace on the CRT.  I decided to let her remainon and "cook" a while ~ after 10-15 minutes - finally, here came a trace!  I have repeated this scenario several times, and I have even put her in the "loop" and monitored my signal FB.  
>> 
>>So, any ideas about what to replace to eliminate the "wait" time? All the tubes are reasonably priced except the 6C10!  That one is pricey! (On, and BTW, I do have the assembly manual and schematic.) 
>> 
>>Thanks for everyones assistance. 
>> 
>>Mike
>> 
>>Chuck, Hayseed has a recap kit listed for an HR 10, but not the HO 10.  But it looks like they would assemble one for me if I requested it. Thanks for the info. 
>>
>>
>>From: "cemilton at aol.com" <cemilton at aol.com>
>>>To: w4gbw at bellsouth.net; k5mlc at sbcglobal.net; heath at puck.nether.net
>>>Sent: Tuesday, July 5, 2011 6:56 PM
>>>Subject: Re: [Heath] HO 10 scope question
>>>
>>>
>>>Try   www.hayseedhamfest.com        They have a complete re-build kit for the scope.  
>>> 
>>>73
>>>Chuck
>>>W4MIL
>>>
>>>
>>>Remember, the government cannot give anything to anyone that they have
>>>not first taken away from someone else.
>>>
>>>
>>>
>>>-----Original Message-----
>>>From: Charles W. Morehouse <w4gbw at bellsouth.net>
>>>To: K5MLC (Mike) <k5mlc at sbcglobal.net>; Heathkit <heath at puck.nether.net>
>>>Sent: Tue, Jul 5, 2011 7:44 pm
>>>Subject: Re: [Heath] HO 10 scope question
>>>
>>>
>>>Hi Mike,
>>>Yes, have restored a couple of them and others with the same circuit.  Replace the HIV caps and all the resistors in the HV circuit.
>>>The electrolytics are unobtanium, but I cut off the base with a Dremmel tool and install new caps inside.  Epoxy the can together.
>>>Works great and keeps the look original.  Suspect the 1V2.  Makes a great scope to monitor your stereo.  Good luck.
>>>Wayne,
>>>W4GBW
>>> 
>>> 
>>>"Madam, we have given you a republic, if you can keep it."  Ben Franklin
>>> 
>>> 
>>> 
>>> 
>>>----- Original Message ----- 
>>>>From: K5MLC (Mike) 
>>>>To: Heathkit 
>>>>Sent: Tuesday, July 05, 2011 4:14 PM
>>>>Subject: [Heath] HO 10 scope question
>>>>
>>>>
>>>>Hello,
>>>> 
>>>>After sitting unused for a while, my HO10 monitor scope appears to be dead.  It was working FB before being shelved.  As far as I know, it has never been recapped.  Should I start there? Anyone have any other ideas/suggestions?? 
>>>> 
>>>>Thanks in advance.
>>>> 
>>>>Mike  K5MLC
>>>>_______________________________________________
>>>>Heath mailing list
>>>>Heath at puck.nether.net
>>>>https://puck.nether.net/mailman/listinfo/heath
>>>>
>>>_______________________________________________
Heath mailing list Heath at puck.nether.net https://puck.nether.net/mailman/listinfo/heath 
>>>
>>>
>
>
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