Re: Repairing flat high voltage ribbon used in HP displays
On 2020-12-05 1:34 p.m., Joel Setton wrote: Hi Toby,
The repair was done more than 30 years ago, and I don't think I remember
all details ! While the epoxy was curing, I think I created pressure on
the flat cable by sticking it tightly between 2 flat and square rubber
blocks (similar to pencil erasers). This ensured that the epoxy layer
was as thin as I could make it, in order to keep the repaired cable thin
and flexible. Fortunately, the delaminated part was not close to the CRT
end of the cable, it was closer to the connector block. But I definitely
remember taking the CRT out of the 181A, because there was no way I
could do a proper repair job if the CRT stayed in the instrument.
If you go the "splicing" way, you may want to check the dielectric
strength of the tubing you'll use. Many heatshrink tubes are rated for
1000 or 1500V, and we're talking several kilovolts on the CRT. Just to That's a good tip, I will need to check. The PDA voltage in the 1331A is 7.5kV. --Toby be on the safe side ! You may also look for a tube which is as flexible
as possible, so as to minimize any mechanical strain on the flat cable
after the repair.
Please keep us posted !
Joel
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Re: hp 8340B YIG UNLOCK error
On Fri, Nov 27, 2020 at 02:23 PM, Raymond Domp Frank wrote:
As said, the stuff quickly dissolved in IPA. No visible traces on the cloth I used. No idea what it was but after removal, the feed-throughs were floating against GND once more. I was quite surprised that the patches had caused not just some leakage at a few 100 kOhms at least but some were below 1kOhm!
I didn't *see* any traces. In a chat with a friend of mine earlier tonight, the thought came up that the problem may have been caused by *silver migration*. Since the bolt/nut and possibly the center conductor may have been made of silver or silver plated, that could well be the problem. Not dissolved in IPA but wiped away! One side of the feed-throughs was inside the die-cast cavities, so not well lit. The visible tarnish may not have been the problem at all! Raymond Raymond
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Re: Weather resistant, covered Litz wire wanted.
This is a copy of a old post (I think mine) from a loop antenna group...
####
For plastics used in RF, you're looking for the compounds with the lowest "loss tangent"/"dissipation factor" (which varies with frequency).
Teflon, polystyrene, polyethylene...
Pretty much anything but PVC!
If you can't buy decent capacitors made with it, it's no good for RF.
See the last column. Compare PTFE to PVC.
has some lovely graphs.
Also, PVC for use in sunlight often has lead in the mix, although they are slowly phasing that out. It's not elemental lead, but still...
####
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On 6/12/20 3:15 am, Chuck Harris wrote: Ordinary PVC is very, very low loss through low microwave frequencies, as is
easily demonstrated by putting a piece in your microwave oven.
Do you have a reference I can look at that shows your assertion?
-Chuck Harris
Andy ZL3AG via groups.io wrote:
Depending on the frequency, PVC's loss tangent will ruin your loop Q, so try to use
HDPE or LDPE instead.
Possible source of litz wire can be transformers used in high efficiency SMPS's, but
the ideal litz wire (wire thickness and qty of wires) changes, even across the MW band.
If you want to build a kick-arse receive loop for MW, I highly recommend the late
Graham Maynard's "Sprial loop with Q multiplier" as found in Practical Wireless - the
best loop I've ever used (feeding into a Racal RA17L).
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Re: 8590B power supply repair
That is the classic symptom of a shorted bridge rectifier on the
power line input of the supply. Replace the bridge, and the 470uf
cap, and you will be on the road to recovery.
RIFA caps rarely do any more damage than smoke... especially here
in 120V land.
-Chuck Harris
Tom B wrote:
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Hello All,
I picked up a clean 8590B SA.? The power supply is bad, HP part number is 0950-1977.?
It acts like a direct short across the AC line (i.e., blows the line fuse
immediately).??? I know about the RIFA cap problem so I will order replacements for
those.? One of the big 470 microfarad electrolytics is bulged a little, but not
leaking.? I will replace both of those.? I also saw a burned resistor.? My question
is; what other parts should I order ahead of attempting the repair?
Tom Bryan
N3AJA
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Hi Folks.
CE Dist is in the same building as Antique Electronic Supply in Tempe, AZ. They are just a wholesale arm of the same company.
You can find CE caps at TubesAndMore.com
Dan in Chandler, AZ
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Re: 8590B power supply repair
Hi Tom,
I am not familiar w/this supply (assume it's NOT from HP) but I would have input diode rectifiers handy (single or bridge) as well as MOSFET's that drive the transformer.
Hope you have a variable AC supply for testing! Good luck.
Mark
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Re: Weather resistant, covered Litz wire wanted.
For a comparison of PVC versus PE (HDPE is just as good), the best source of dielectric loss mesurements is Von Hipples work from MIT, around WWII. Since you may not have his text book, can download the data from "Tables of Dielectric Materials" from DTIC.MIL, I think that's the Defense Technical Info Center. Google it, and Von Hipples name. Once you downloaded the PDF, look at page 116 for polyvinyl Chloride and page 153 for polyethylene. Dielectric constants for both are relatively similar. But look at loss tangent. At 1 MHz PVC is 0.016, PE is 0.0002. And you can see similar difference up to 10^7 (10 MHz) and 10^8 Hz. In RF heating (which is the effect that loss give), the loss tangent is directly related as is frequency. Electric field is a squared term. I would not recommend PVC insulation on anything that has high RF voltage in the MHz, unless you don't mind the loss and the part is cooled. Using PVC pieces as spiders for an open wire RF transmission line that is matched is probably OK, but not in a resonant circuit where the electric field rises. So it depends on the application. PVC is a very polar molecule like water, having a net dipole moment. These little dipoles are what causes the loss. Don't forget that a microwave oven at 2450 MHz has a low field strength as it is not a single resonant mode, in fact the fields are bouncing all around. When I worked for DuPont years ago, I was in the dielectric heating group. We would get chemists all the time saying "this stuff is great, I put in in my microwave oven and it only warmed in xx minutes." To which we would open the cover of our 90 Mhz WT LaRose heater with about 15 kV across the plates, and the PVC would catch on fire in 10-20 seconds. Believe me, I have done this dozens of times to prove out various hose and insulation materials in high power RF amplifiers in my workplace.
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8590B power supply repair
Hello All,
I picked up a clean 8590B SA.? The power supply is bad, HP part number is 0950-1977.? It acts like a direct short across the AC line (i.e., blows the line fuse immediately).??? I know about the RIFA cap problem so I will order replacements for those.? One of the big 470 microfarad electrolytics is bulged a little, but not leaking.? I will replace both of those.? I also saw a burned resistor.? My question is; what other parts should I order ahead of attempting the repair?
Tom Bryan
N3AJA
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Before you can view the prices you need to register, when you do this you have to declare that the products are not for personal use and submit your business details.
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------ Original Message ------
From: "Eric Boyle via groups.io" <k0elb@...>
To: [email protected]
Sent: Saturday, 5 Dec, 20 At 14:08
Subject: Re: [HP-Agilent-Keysight-equipment] Can capacitors
Here's their sales website:
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Re: Weather resistant, covered Litz wire wanted.
Donald,
Out of curiosity, are you trying to receive a single frequency or a band of frequencies.? If you are seeking a single frequency with rather high Q, there is a simpler solution.
Bruce, KG6OJI
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Re: 8590B low sensitivity problem
Not sure if the 8590 has , but the early HP SAs had a fuse in the input N connector, you maybe lucky
Check between the center pin of the N connector and the end of the cable attached measure the resistance
Richard
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On 05/12/2020 18:35, victor smith wrote: Hi
I do not have a chart of correct signal levels handy. Based on experience though, the vast majority of the time the symptoms you mention point to a blown first mixer. The sttenuator also is a common culprit in large losses of amplitude, but normally would show a flat frequency response. The ¡°hi pass¡± response you mention is indicative of an open coaxial cable or most probably a blown (by too much power applied) mixer.
Try visually inspecting all the input cabling. On my 8594, the attenuator is in front of the first mixer, if I remember right. 70 db is an awful lot of amplitude to lose! You can try bypassing the attenuator (inject a signal at the output cable) to check for fault there. Dont put more than around 0dbm into that mixer input!
--
Best wishes /73
Richard Bown
Email : richard@...
HTTP :
######################################################################
Ham Call: G8JVM . QRV: 50-432 MHz + Microwave
Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W
QRV 6mtrs 200W, 4mtrs 150W, 2mtrs 300W, 70cms 200W,
Microwave 1296MHz 110W, 2320MHz 100W, 5760MHz 10W & 10368MHz 5W
OS: Linux Mint 20, on a Dell Inspiron 3580 laptop
######################################################################
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Re: 8590B low sensitivity problem
Hi
I do not have a chart of correct signal levels handy. Based on experience though, the vast majority of the time the symptoms you mention point to a blown first mixer. The sttenuator also is a common culprit in large losses of amplitude, but normally would show a flat frequency response. The ¡°hi pass¡± response you mention is indicative of an open coaxial cable or most probably a blown (by too much power applied) mixer.
Try visually inspecting all the input cabling. On my 8594, the attenuator is in front of the first mixer, if I remember right. 70 db is an awful lot of amplitude to lose! You can try bypassing the attenuator (inject a signal at the output cable) to check for fault there. Dont put more than around 0dbm into that mixer input!
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Re: Repairing flat high voltage ribbon used in HP displays
Hi Toby,
The repair was done more than 30 years ago, and I don't think I remember all details ! While the epoxy was curing, I think I created pressure on the flat cable by sticking it tightly between 2 flat and square rubber blocks (similar to pencil erasers). This ensured that the epoxy layer was as thin as I could make it, in order to keep the repaired cable thin and flexible. Fortunately, the delaminated part was not close to the CRT end of the cable, it was closer to the connector block. But I definitely remember taking the CRT out of the 181A, because there was no way I could do a proper repair job if the CRT stayed in the instrument.
If you go the "splicing" way, you may want to check the dielectric strength of the tubing you'll use. Many heatshrink tubes are rated for 1000 or 1500V, and we're talking several kilovolts on the CRT. Just to be on the safe side ! You may also look for a tube which is as flexible as possible, so as to minimize any mechanical strain on the flat cable after the repair.
Please keep us posted !
Joel
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Re: Can you ID these Tracking Generator parts please?
Hi?
I don't see any one replying to you on this.
i did some more research and maybe the bottom TG is the?5087-7705 BITG with Option HSB which is a 3Ghz BITG
Like you there is concern both show signs of being opened as labels on the BITGs are missing
Sandra
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That first one appears to be a good candidate for one of the HP-410C's filter caps.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Orin Eman" <orin.eman@...>
To: [email protected]
Sent: Saturday, December 5, 2020 11:51:34 AM
Subject: Re: [HP-Agilent-Keysight-equipment] Can capacitors
Just take the SKU off that site and search for it. There are many
vendors. The first one, C-EC20X4-475 (4x20uF, 475V) goes for about $40.
Not that I need any, but useful information to know that they exist IMO.
On Sat, Dec 5, 2020 at 9:33 AM Eric Boyle via groups.io <k0elb=
[email protected]> wrote:
And after posting that link I found out that you have to have a business
to buy from them. They apparently won't sell to individuals. Shame.
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Just take the SKU off that site and search for it.? There are many vendors.? The first one,?C-EC20X4-475 (4x20uF, 475V) goes for about $40.
Not that I need any, but useful information to know that they exist IMO.
And after posting that link I found out that you have to have a business to buy from them. They apparently won't sell to individuals. Shame.
|
And after posting that link I found out that you have to have a business to buy from them. They apparently won't sell to individuals. Shame.
|
[test-equip-trader] Maury N fm cal kit
For sale Maury Nfm cal kit,? 18GHz,? model 8850Q01
Location¡ Ft. Mill, SC USA
Payment¡ check on US bank,? PO. MO,? western union,? bank wire transfer.?
$385 shipped CONUS outside US additional
Pete wa2odo
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[test-equip-trader] 3.5mm Maury m and fm cal kit
For sale? Maury model 80500 - 03, 3.5mm m and fm,? with 3.5mm thru.? ?$895 Shipped CONUS
Pete wa2odo
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[test-equip-trader] Partial cal kit
For sale is a partial Wiltron (Anritsu) SMA/3.5mm cal kit.? ?Has¡ box (worth $75),? M sliding load (worth $75+), fm sliding load (worth $75+),? 3 apc7 to sma adapt( worth $110)? spare tips for sliding loads (worth $50) micrometer depth gage with ref's ($100)¡ . $290 shipped CONUS.?
Payment¡ cash in person,? check on US bank,? western union,? and bank transfer.? ?No paypal
Location.? .. Ft. Mill,? SC,? USA 29707
More pics svailable
Pete wa2odo
Pete WA2ODO,_._,_
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ebrucehunter
Eric Boyle
