PMEL Forum

K Sections => K1/8 - DC/Low Frequency => Topic started by: RichieRich on 12-05-2008 -- 14:09:13

Title: Rejuvinating HP tubes
Post by: RichieRich on 12-05-2008 -- 14:09:13
Lots of the older HP equipment out there (8566, 3577, 3585, etc) is still usable but tubes are becoming dim, unfocused, etc.  I have sent a couple of tubes out to a vendor who rejuvinates them with pretty good success in the past, but I'm interested in doing it in-house with a sencore CR7000.  Should be easy stuff but the sencore literature gives setup information for thousands of tubes, but I don't see any of the HP part numbers. 

Has anyone else had any experience with this?  Any tube data out there somewhere?
Title: Re: Rejuvinating HP tubes
Post by: mdbuike on 12-05-2008 -- 15:41:37
If you have some spare bad tubes, try, carefully, taking off the old HP label and see if the original manufacturer is on there, since, as I recall, HP didn't make the CRTs, just used them.

I noticed this when I was replacing an 8566's CRT with the Agilent kit, that the new CRT was not from Agilent, but I forget who (it's been a lot of years since then, and I'm doing fiber now).

Those setups might be in the Sencore manual...also, sometimes HP put the original manufacturer's PN in thier tech manuals.

Hope it helps,

Mike
Title: Re: Rejuvinating HP tubes
Post by: RichieRich on 12-05-2008 -- 16:35:56
I don't know that HP made all of them but I know they made at least some.  I have worked with Richardson Electronics to buy replacement tubes for some items and they confirmed for me when I was trying to replace the tube in an 8562A, that it was manufactured by HP and they couldn't help.  The ones I am looking at now (from 3585A's) only have HP stickers without anything underneath.
Title: Re: Rejuvinating HP tubes
Post by: Bryan on 12-09-2008 -- 16:25:40
For what it's worth I had a 3585A that was getting fuzzy a couple years ago.  I was able to straighten it out by removing the covers and blowing several years of accumulated dust out of it.  It goes without saying exercise some caution to protect your eyes & make sure your compressor isn't blowing out watre vapor.

Seems like I recall some Panasonic tubes in 8590 series, if you locate a replacement for your 3577 please post it, mine is getting dim.
Title: Re: Rejuvinating HP tubes
Post by: RichieRich on 12-10-2008 -- 09:04:58
Yeah, I'm working with some 3585A tubes right now.  So far I'm one for three.  I made one better and two worse.  Regarding the 3577A, I did have some luck because I had an old 8562A scrapped out with a good tube remaining.  They use the same CRT.  Seems like for some reason the 3577A's were harder on tubes than 8562A's though they use the same CRT.  You can hardly find a 3577A with a decent tube today.
Title: Re: Rejuvinating HP tubes
Post by: Bryan on 12-10-2008 -- 15:31:41
Thanks for the interchange info.
Title: Re: Rejuvinating HP tubes
Post by: Hawaii596 on 02-17-2009 -- 10:44:03
Not to slightly change the subject, but has anyone had experience with the new retrofit kits for the Tek TDS 500/600/700 series scopes (such as TDS784, etc.)?  I've seen ads by a lab that has an LCD retrofit (remove the weak CRT and replace it with a color LCD - probably plus some other extra hardware).

Just wondering if anyone has tried it.  I can give the company name if anyone wants it.
Title: Re: Rejuvinating HP tubes
Post by: RichieRich on 02-18-2009 -- 09:07:02
You're probably talking about Norway Labs.  I had a scope done by them and may have another done soon.  I was overall happy with the result - sent it in to them to be done at their facility because the install was free.  If I had any complaint it is that the LCD might have been a little smaller than the CRT so there was a little "frame" or dead area inside the bezel.  I didn't have an original scope with CRT sitting next to it to compare though so it might not be a fair criticism.  I am sure I will use their service again at some point if not within the next few weeks.
Title: Re: Rejuvinating HP tubes
Post by: Hawaii596 on 02-18-2009 -- 13:49:42
We have an application where we specifically need a TDS694C (if anyone knows of a low priced used one, let me know).  It is for some Tektronix TLA series logic analyzers.  There is only one way to cal them using the cal fixture (which we are VERY lucky to have - Tek doesn't sell them any more).  The closed loop software calls for a TDS694C and won't work with any other model.

So we need to find a budget priced one.  I'm thinking maybe there's one with a dim CRT we could get for cheap and have an LCD retrofit done..
Title: Re: Rejuvinating HP tubes
Post by: RichieRich on 02-19-2009 -- 15:46:13
You're probably looking at a minimum of about $8k for a TDS694C from a reputable dealer. You might be able to snag one on ebay for closer to $5k - but that's not for everyone.  If you bide your time, you may see one on ebay with a bad display go for closer to $2k.  It all depends on how patient and risk tolerant you are.  Also I would caution you to make sure the scope doesn't need any options to be compatible with the software or fixture.  I would be happy to help if you want to pm me.
Title: Re: Rejuvinating HP tubes
Post by: sreaves on 03-18-2012 -- 11:11:29
I have a HP8566 with a very weak tube, otherwise it is perfect. If anyone has an update to this post or a link to a company that can repair these tubes I would appreciate any help. Thank you.

Sam
W3OHM
Title: Re: Rejuvinating HP tubes
Post by: dminesinger on 03-18-2012 -- 12:10:59
http://testequipmentplus.com/ has an LCD kit for replacing the tube. We did an HP/8562E and it worked great. Was very happy with the results.



Quote from: sreaves on 03-18-2012 -- 11:11:29
I have a HP8566 with a very weak tube, otherwise it is perfect. If anyone has an update to this post or a link to a company that can repair these tubes I would appreciate any help. Thank you.

Sam
W3OHM
Title: Re: Rejuvinating HP tubes
Post by: RFCAL on 03-18-2012 -- 13:03:49
I know we have a few, both good and bad (some with display issues).
Title: Re: Rejuvinating HP tubes
Post by: retiredAFinSD on 03-19-2012 -- 09:01:57
Techmaster located on the west coast is one of the labs that will repalce the CRT with a LCD and they work great. Have not heard any complaints from any customers.

Title: Re: Rejuvinating HP tubes
Post by: yonker08 on 03-19-2012 -- 16:23:44
If you want to take a chance you could probably find one at this site: http://www.govliquidation.com/. The bids start at $150 plus any expense to get it to you. I have seen some 8566s recently I believe they were out of OK City.
Quote from: sreaves on 03-18-2012 -- 11:11:29
I have a HP8566 with a very weak tube, otherwise it is perfect. If anyone has an update to this post or a link to a company that can repair these tubes I would appreciate any help. Thank you.

Sam
W3OHM
Title: Re: Rejuvinating HP tubes
Post by: RichieRich on 03-20-2012 -- 16:52:00
We have installed a few of the LCD upgrade kits for 8566 spec-ans.  There are several places that will sell you the kit / installation but I believe they all come from here - http://testequipmentplus.com/

You can buy the kit and do the install yourself if you prefer or you can pay them to do it.  A third party installer might do it just as cheap as Test Equipment Plus if they have purchased the kits in quantity at a discount, but that's where they get theirs from.
Title: Re: Rejuvinating HP tubes
Post by: Hawaii596 on 03-26-2012 -- 10:55:53
We've done two kits so far on an HP 8566B and Tek TDS694C.  Both working nicely.  We had a vendor do the TDS694C kit, and we did the 8566B kit ourselves.  To be fully fair, a friend at another lab had one done on an 8563A Spec An a couple of years ago, and they had a weird glitchy problem with theirs.  The trace portion of the display disappeared a few times and the only way they could clear the error was an HPIB command (not with front panel reset).  He said the problem went away.  On our 8566B kit, we screwed up the install the first time and mis-aligned a 16 pin dip plug on a ribbon cable, so watch out for that.  But I am definitely a big fan.  I love the 8566B and and using it right now out on the road.  It has a color display now thanks to the kit.  Don't mean to peddle other people's products, but it is a great little kit (I receive no royalty for these remarks).