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Re: HP6643A - Blows Fuse When Activated

 

if the fuse blows when activated, then something downstream of the fuse, (once activated) is likely a short.? Assuming that the high amperage fuse blows roughly as fast as the low amperage fuse (don't try to measure it......) then you're likely looking at a dead short downstream of the fuse.

Harvey

On 4/6/2024 7:18 PM, Michael Yellin wrote:
Mates,

Recently acquired an HP 6643A.? When the unit is plugged in and turned on, it boots, and seems fine.? However, as soon as the unit is "activated" to generate voltage and amperage, the glass fuse blows.? I don't have an endless supply of fuses, but I have tried some very low and very high voltage and amperage settings, but that made no difference (I didn't think it would, but well, it made me feel better to try)? Opened her up, looked around, and everything appears fine, no burnt parts, no bulging caps, no melted wires, and nothing obviously shorted.? Anyone have any ideas what could be wrong, or can send me down a path to try and resurrect the thing.

TIA
Michael
Re: Anyone with a 3586B A80 board?

 

Matt sorry to hear the issue and yes indeed lots of risk these days.
I was going to say homebrew a replacement. Without that Da$% leaky battery.
It shouldn't be to bad. I have had to do that for other HP gear like the 3335 sig gen. It's great when it comes back alive.?
Ok caution. If the leakage from the battery hit the motherboard?its seriously has to be cleaned up down to scraping the board. My experience?was with the actual regulator board and the?stuff conducts very well.
I thought I had it cleaned at least visually but had super strange results. Thats when I discovered trace to trace leakage was the issue.
Digging out the traces carefully cleared the?issue completely. The stuff even gets under resistors.
Good luck.
Paul
WB8TSL
HP6643A - Blows Fuse When Activated

 

Mates,

Recently acquired an HP 6643A.? When the unit is plugged in and turned on, it boots, and seems fine.? However, as soon as the unit is "activated" to generate voltage and amperage, the glass fuse blows.? I don't have an endless supply of fuses, but I have tried some very low and very high voltage and amperage settings, but that made no difference (I didn't think it would, but well, it made me feel better to try)? Opened her up, looked around, and everything appears fine, no burnt parts, no bulging caps, no melted wires, and nothing obviously shorted.? Anyone have any ideas what could be wrong, or can send me down a path to try and resurrect the thing.

TIA
Michael
Re: 8510C - calibration 3.5/sma

 

I would think that they are corrections for the open in the cal kit. By any chance did you not use the small insert pin with the open?

I have used the 8510C, but am not an expert by any stretch. There are others on this forum that have more knowledge.

Don Bitters
Re: Anyone with a 3586B A80 board?

 

It's gotten so bad lately that I bring a power pack and inverter and give things a quick check while I'm still at these flea markets.

Interesting that when I mention I'm bringing an item to my car to check it out so many sellers all of a sudden remember problems. Amazing how much a 120 volt inverter can help memory!

On 4/6/2024 5:13 PM, Matt Harris wrote:

I g?o?t? ?r?i?p?p?e?d? ?o?f?f? picked up a 3586B at the Raleigh, NC hamfest this weekend, and the "gentleman" who sold it to me assured me it powered up with no problems, he and his buddy he was there with just checked it all yesterday to make sure there were no issues with it.? I took it home and before applying power, I knew I needed to check the A80 board for bad batteries.? The good thing is that there were no bad batteries on the board.? The bad thing is that this is because the A80 board is totally missing, and indeed the ones that used to be there in the past had leaked all over, and the motherboard has some damage as a result.? At the very least, I'll have to replace some connectors.? I sure hope I see this "gentleman" in the future.? And if he's in this group, all I can say is, you know who you are, and I? ?h?o?p?e? ?m?a?g?g?o?t?s? ?e?a?t? ?y?o?u?r? ?t?o?n?g?u?e? ?f?r?o?m? ?y?o?u?r? ?l?y?i?n?g? ?m?o?u?t?h?.??God bless you.
Do any of you happen to have an extra A80 board for this that I could purchase reasonably to save me from having to make an equivalent? Oh, and it is also missing the entire A16 reference oscillator board - I think I have a spare for that, but I'm not 100% sure, so if you have just the board (I know I have a compatible oscillator module) I'd appreciate being able to purchase that as well.

Regards,
Matt
Anyone with a 3586B A80 board?

 

I g?o?t? ?r?i?p?p?e?d? ?o?f?f? picked up a 3586B at the Raleigh, NC hamfest this weekend, and the "gentleman" who sold it to me assured me it powered up with no problems, he and his buddy he was there with just checked it all yesterday to make sure there were no issues with it.? I took it home and before applying power, I knew I needed to check the A80 board for bad batteries.? The good thing is that there were no bad batteries on the board.? The bad thing is that this is because the A80 board is totally missing, and indeed the ones that used to be there in the past had leaked all over, and the motherboard has some damage as a result.? At the very least, I'll have to replace some connectors.? I sure hope I see this "gentleman" in the future.? And if he's in this group, all I can say is, you know who you are, and?I? ?h?o?p?e? ?m?a?g?g?o?t?s? ?e?a?t? ?y?o?u?r? ?t?o?n?g?u?e? ?f?r?o?m? ?y?o?u?r? ?l?y?i?n?g? ?m?o?u?t?h?.??God bless you.
Do any of you happen to have an extra A80 board for this that I could purchase reasonably to save me from having to make an equivalent???Oh, and it is also missing the entire A16 reference oscillator board - I think I have a spare for that, but I'm not 100% sure, so if you have just the board (I know I have a compatible oscillator module) I'd appreciate being able to purchase that as well.

Regards,
Matt
Re: 5328A counter

 

So I had to look it up after thinking some. The transformer circuit is pretty conventional, so should be easy to troubleshoot. The transformer is always activated, so the OCXO option can run always, and the supply regulators are enabled by the power switch. There is a TRIAC circuit, but just for the fan, so it won't run all the time - only when turned on.

Anyway, you should have raw power whenever the unit is plugged into line. An easy way to trace the action is to unplug it and look at the resistance between the plug prongs and to points inside like the line fuse and voltage selector and so on.

Ed
Re: 5328A counter

 

My long-term memory for short-term events could be entirely wrong on this, but I recall working on some 3528As (all ultimately junked out) long ago, and vaguely that there's an "electronic" power switch function in there. IOW, there's a thyristor circuit or relay or something so the power switch on the front is at low voltage, and remotely activates the circuit. I remember thinking it was ridiculously complicated, had lots of problems, and would be unreliable, which was part of the decision process to junk them out - not worth the trouble. I was highly unimpressed with the design and build quality of that product.

Again, I could be all wrong here and may be thinking about something else, but you should thoroughly study the power supply schematics and understand how it all works before digging in too deeply. Good luck.

Ed
Re: 5328A counter

 

That is a dual primary power transformer, with a selector switch. Dirt contacts in the switch It looks like it is on the rear panel, next to the fuseholder. If run on 240, a single bad winding would kill the transformer, but both would have to be bad? for 120 volt operation. Those slide switches often fail from old age. The grease in them dries into a non conductive film, or causes the plastic to crumble. I've replaced them in a lot of things since the mid '60s.
Do a search for 'voltage selector slide switch' to find ones with the flush actuator.if yours is bad.


On Sat, Apr 6, 2024 at 2:46?PM Tom Lee <tomlee@...> wrote:
If you have verified that there is proper voltage at the primary itself,
and the absence of any output from the secondary without any shorting of
the latter, then I think you're able to draw the proper conclusion. Just
make sure you are truly measuring these quantities at the transformer.

Long-working transformers rarely go open-circuit quietly and without
olfactory cues. If they do, then it's often something simple, like
stress finally breaking a transformer winding lead from a terminal,
perhaps due to someone flexing an assembly in the act of repairing
something else. Just look carefully and check for such things.

Good luck!

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070


On 4/6/2024 6:58 AM, Joe White wrote:
> I have recently replaced most of the electrolytic caps and the
> on/switch on this device.? Instead of inconsistently turning on and
> off, it will not turn on at all.? The standby light does not
> illuminate when the device is plugged in.? I have 120 VAC to the
> transformer and no voltage downstream the transformer.? All fuses are
> correct size and intact, no shorts detected at the fuse holders.? I
> get zero voltage readings at all voltage test points on all pcbs.? I
> would appreciate any ideas on what may be wrong, what else to test.
Re: 5328A counter

 

If you have verified that there is proper voltage at the primary itself, and the absence of any output from the secondary without any shorting of the latter, then I think you're able to draw the proper conclusion. Just make sure you are truly measuring these quantities at the transformer.

Long-working transformers rarely go open-circuit quietly and without olfactory cues. If they do, then it's often something simple, like stress finally breaking a transformer winding lead from a terminal, perhaps due to someone flexing an assembly in the act of repairing something else. Just look carefully and check for such things.

Good luck!

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

On 4/6/2024 6:58 AM, Joe White wrote:
I have recently replaced most of the electrolytic caps and the on/switch on this device.? Instead of inconsistently turning on and off, it will not turn on at all.? The standby light does not illuminate when the device is plugged in.? I have 120 VAC to the transformer and no voltage downstream the transformer.? All fuses are correct size and intact, no shorts detected at the fuse holders.? I get zero voltage readings at all voltage test points on all pcbs.? I would appreciate any ideas on what may be wrong, what else to test.
Re: Service Notes on HPWiki

 

Nice work! :)

If you ever come across anything for the 8160A, I'd be super appreciative!



Thanks for all your efforts!
Jared
Looking for internal photos of 04284-65007 'Interface Box'

 

I'm looking to build myself an 04284-65007 Interface Box' to aid in performance testing my LCR meters.
From the 4263B manual, I have been able to mostly infer the connections to the 'DC Bias' connection, but so far I've been unable to figure out exactly how the 'Test Signal' connection is made.
I think it's pretty simple, but I just want to make sure I get it right...

Does anyone have one of these boxes that they can lift the lid on and take a couple photos of what's inside?


Thanks!
Jared
Re: 5328A counter

 

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Well, assuming you are measuring 120 V actually across the transformer primary windings (BLK/YEL & BLK or BLK/RED & BLK/GRN) and the line voltage selector switch? is correctly set (and working) and there is nothing in the way of an AC voltage actually on the secondary wires out of the transformer, sounds like a transformer winding has failed open circuit, but the chance of that happening exactly when you changed the caps and switch, while possible, I would rate as unlikely?
If there is no secondary voltage and the fan is not running either..... then it's really odd........I think that really means the line/neutral voltage ain't getting to where it should?

On 06/04/2024 14:58, Joe White wrote:

I have recently replaced most of the electrolytic caps and the on/switch on this device.? Instead of inconsistently turning on and off, it will not turn on at all.? The standby light does not? illuminate when the device is plugged in.? I have 120 VAC to the transformer and no voltage downstream the transformer.? All fuses are correct size and intact, no shorts detected at the fuse holders.? I get zero voltage readings at all voltage test points on all pcbs.? I would appreciate any ideas on what may be wrong, what else to test.? This unit is just one more problem from the scrap yard.

Thanks
--
Joe White
KW4YW

5328A counter

 

I have recently replaced most of the electrolytic caps and the on/switch on this device.? Instead of inconsistently turning on and off, it will not turn on at all.? The standby light does not? illuminate when the device is plugged in.? I have 120 VAC to the transformer and no voltage downstream the transformer.? All fuses are correct size and intact, no shorts detected at the fuse holders.? I get zero voltage readings at all voltage test points on all pcbs.? I would appreciate any ideas on what may be wrong, what else to test.? This unit is just one more problem from the scrap yard.

Thanks
--
Joe White
KW4YW
Re: 8510C - calibration 3.5/sma

 

BTW, SMA (normally to 18 GHz), 3.5 mm (to 26.5 GHz), and 2.92 mm (K connector, to 40 GHz) are mechanically compatible.? 2.4 mm (to 50 GHz) and smaller will not mate with those 3 (long story about HPAK vs. Wiltron (now Anritsu) rivalry to blame).? IIRC, 1.85 mm (V connector, to 67 GHz) mates with 2.4 mm.? I'm not sure about the 1.0 mm (to 110 GHz) and the newer 1.35 mm (to 86 GHz) connectors.

I've also heard of the 0.9 mm and 0.8 mm connectors but not about anyone actually using them.? I can imagine how much those cost.? Last I knew, about 10 years ago, the 1.0 mm Southwest Microwave connectors were about $1000 apiece!

HTH.

Jim Ford
Laguna Hills, California, USA

"And we know that God causes all things to work together for the good of those who love God and are called according to his purpose for them." Romans 8:28 (NLT)


------ Original Message ------
From "Tom via Metronet" <n8zmTWH@...>
Date 4/5/2024 8:26:36 AM
Subject Re: [HP-Agilent-Keysight-equipment] 8510C - calibration 3.5/sma

³¢±ð´Ç²Ô¡­

?

When you perform a calibration, you need a short, open, load, and thru. It looks like you have pulled up all the standards all of the defined standards in that kit. Note that there are different connectors (3.5, 2.92, 2.4, 1.85, SMA ) listed in the labels column. Those are not all compatible with each other so not sure why they are listed. Cal Kit definitions are kind of arcane exercises.

?

Tom, N8ZM

?

From: [email protected] <[email protected]> On Behalf Of LeonP
Sent: Friday, April 5, 2024 4:03 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8510C - calibration 3.5/sma

?

Any ideas, what the red circled elements are for?
Re: Service Notes on HPWiki

 

On Mon, Apr 1, 2024 at 04:06 PM, Wolfgang Schraml wrote:
We now have more than Keysight has on their dedicated Service Notes site () - over 4000!
?
I was looking for a product note ... no longer available on Keysight ... (or anywhere else I could find that wasn't behind a paywall) but I found it here! Great resource, thanks.
Re: HP 427A no DC offset adj. pot

 

The only option listed on mine is H32. I read somewhere that referred to the line fuse. The yellow calibration sticker has the comment ¡°Battery not used. Use line voltage for TI power requirements.¡±

³¢±ð´Ç²Ô¡­
Re: 8510C - calibration 3.5/sma

 

Only use SMA to 3.5mm adaptors on the cables if the DUT has 3.5mm connectors. Otherwise you are just adding another variable.
Re: 8510C - calibration 3.5/sma

 

¿ªÔÆÌåÓý

³¢±ð´Ç²Ô¡­

?

When you perform a calibration, you need a short, open, load, and thru. It looks like you have pulled up all the standards all of the defined standards in that kit. Note that there are different connectors (3.5, 2.92, 2.4, 1.85, SMA ) listed in the labels column. Those are not all compatible with each other so not sure why they are listed. Cal Kit definitions are kind of arcane exercises.

?

Tom, N8ZM

?

From: [email protected] <[email protected]> On Behalf Of LeonP
Sent: Friday, April 5, 2024 4:03 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8510C - calibration 3.5/sma

?

Any ideas, what the red circled elements are for?
Re: 8510C - calibration 3.5/sma

 

Any ideas, what the red circled elements are for?
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