Author Topic: HP3568B hints and tips?  (Read 792 times)

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Offline tkamiya

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HP3568B hints and tips?
« on: April 11, 2019, 11:52:55 pm »
HP3568B Selective level meter came into my possession quite unexpectedly.  Any hints and tips, such as check THIS and be careful with THAT will be appreciated.  It was so remote that this will happen, I'm not prepared. 

I know to check the battery but I don't know where it is located.  The weird WECO connectors are in route. 
 

Offline wn1fju

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Re: HP3568B hints and tips?
« Reply #1 on: April 12, 2019, 01:42:10 am »
I assume you mean HP 3586B, not HP 3568B.

You are correct to check the battery on board A80.  If they have leaked, do not turn the power on until the board is repaired.  Otherwise, you may take
out some of the pass transistors and Zeners that feed the board.  Or even worse - my A80 board actually caught fire!

Go to Keysight's website and download the four volume manual set if you haven't already.

It takes a little practice to effectively use the piece, especially if you want to hook up an antenna and use it as a general purpose HF receiver.  Read the
op manual.

Otherwise, the 3586B is built like a tank in typical 1980's HP fashion.
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #2 on: April 12, 2019, 02:04:22 am »
Yes, you are right.  It's HP 3586B. 

I will check and replace the battery on priority tomorrow.  I certainly do not want fire in my lab!  Another thing I want to do is to replace that LITTLE knob.  I have some old Yaesu's that are being parted, so I'll probably use it's main dial.  May not look right but should be more readily functional as a receiver. 

If I have to replace this, if I just unsolder the battery, what would the memory lose?  I hope it's not the backup for system software, but rather user setting, etc?  Would calibration going to be lost? 

I was little concerned with hooking up an antenna and doing so in more less permanently.  Is it's input protected from static charge?  I have a long wire antenna that is about 30 meter long. 

Yes, it is built like a tank.  Inside kind of resembles signal generator from the same period.  I think it was something like $12000 new?
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #3 on: April 12, 2019, 03:31:33 am »
Will you please verify this battery is 2.4 volt?  Mine is showing 1.5 volt.  I'm sure it is original.  Some corrosion is there but not leaking.  I'm going to replace this.  I'm sorry, I know nothing about this board.  Is this supposed to be a Nicad, considering it's 80s equipment?
 

Offline wn1fju

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Re: HP3568B hints and tips?
« Reply #4 on: April 12, 2019, 12:14:28 pm »
Please download the op and service manuals.  A lot of your questions can be answered from them.  And perhaps this thread should be moved to the
Repair forum rather then the Metrology forum.  Although the 3586B is a nice piece of equipment, it is hardly a metrology item! 

But to answer your immediate question, the battery is ~2.5V as necessary to keep some of the RAM chips alive when the unit is powered off (in order
to save user configurations).  The battery is not crucial to the operation of the 3586B.  In fact, I just looked at my unit, which hasn't been turned on
in a long time, and the battery voltage is down to about 0.5V.  When I replaced mine, I used two 1.2V NiCd batteries.  They are trickle charged by the
power supply when the unit is on.  The unit should still work fine even if the battery is removed.

I'm not so sure I would leave an antenna hooked up permanently unless it is to one of the jacks that is cut off by the various input relays when the
unit is off.  There probably isn't a whole lot of input protection once it gets past the input switching board and heads off to the amplifier/mixer.  And
even if you are connected to a line that is cut off, a lightning strike will certainly ruin your day.  Pretty simple solution:  unplug the coax when not in use.
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #5 on: April 12, 2019, 01:49:51 pm »
Yes, and yes.  I will read the manual.  I just needed to order the battery fast.  So thank you very much for answering my question.  I ordered cordless phone type package. 

OK on antenna connection.  You are right.  This is not a rig, it's a test instrument.  I understand.  This is a measuring equipment but it's not a "precision" equipment.  I'm sorry.

I'll report myself to mod and have it moved.
 

Offline Tony_G

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Re: HP3568B hints and tips?
« Reply #6 on: April 12, 2019, 08:15:15 pm »
I've thought about picking one of these up, would love to see a post or video on it in use.

TonyG

Offline tautech

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Re: HP3568B hints and tips?
« Reply #7 on: April 12, 2019, 08:28:14 pm »
I'll report myself to mod and have it moved.
As OP you can move it yourself.
Look for the Move Topic button at the foot of your page.
Avid Rabid Hobbyist
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #8 on: April 12, 2019, 09:06:13 pm »
If someone wants to see it in use, there already is a few video out there.  Just google on the "HP" and model number without the A, B, C suffix.  I'm cleaning mine, so it is out of order at the moment.

Thanks for the tip of doing it myself.  I will remember to do so next time.
 

Offline wn1fju

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Re: HP3568B hints and tips?
« Reply #9 on: April 12, 2019, 09:54:41 pm »
There are lots of web pages devoted to the use of the 3586(A/B/C) as a general purpose receiver.  It is particularly nice below 1 MHz where most
modern receivers start to sacrifice sensitivity.  I can hook mine up to my ground mounted HF vertical in my yard and listen to AM broadcasts at night.
I hear a readable AM broadcast station pretty much every 10 kHz across the entire AM band (in the USA). 
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #10 on: April 12, 2019, 10:19:20 pm »
I actually want to hear WWVB.  I use it, but never heard what it sounds like in audio.
 

Offline 0culus

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Re: HP3568B hints and tips?
« Reply #11 on: April 12, 2019, 10:22:37 pm »
FWIW, you can call their phone number and hear the same signal that is broadcast. [edit] This is for WWV and WWVH, my bad.
« Last Edit: April 12, 2019, 10:46:12 pm by 0culus »
 

Offline tkamiya

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Re: HP3568B hints and tips?
« Reply #12 on: April 12, 2019, 10:34:22 pm »
WWVB (B) is digital only, I thought?  I'm not talking about WWV.
 

Offline 0culus

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Re: HP3568B hints and tips?
« Reply #13 on: April 12, 2019, 10:38:10 pm »
WWV also broadcasts the encoded time. You hear it between the voice announcements. I thought the encoded part was the same between them? [edit] you're right, WWVB doesn't modulate the time signal as audio.
« Last Edit: April 12, 2019, 10:46:29 pm by 0culus »
 

Offline N2IXK

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Re: HP3568B hints and tips?
« Reply #14 on: June 21, 2019, 12:54:45 am »
These are very nice instruments. Just finishing up the resurrection of one that had been written off by a previous owner due to the battery leakage issue.  Somebody had unfortunately powered it up with the damaged A80 board, and blew the line fuse. Further troubleshooting found the 5V pass regulator transistor (Q3) to be defective (open emitter--internal bond wire melted), and the big zener diode (CR20) from the emitter to ground shorted. 5V supply must have "shot for the moon", causing the zener to conduct heavily and overheat.  Transistor is easy enough to get (I found an OEM HP part on eBay for a few bucks, but NTE makes an equivalent NTE245 for about $5. It is a 10A NPN darlington. The zener diode was the painful one. Anyone bought a 6.2V 10W studmount zener recently? Better part of $30 for the NTE equivalent (NTE5180A), and that was about the only source I could find.  The HP part (1902-1217) used to be available from Sphere for cheap, but he sold them out.  There is an obscure note in the manual concerning this part. Apparently early production units used a 5.6V zener, but a production change shifted to 6.2V due to excessive current draw causing objectionable ripple on the 5V rail.  The mounting of the diode is also not optimal. They put a toothed solder lug for a ground wire between the diode body and the heatsink, and bolted the diode down with no heatsink grease.  I moved the ground lug to one of the screws that secures the thermal switch, and put some heatsink grease between the grounded diode case and the heatsink to improve cooling.

The other internal carnage that needed to be dealt with was the edge connector for the A80 board. It was heavily corroded by the electrolyte leakage. Fortunately, the damage didn't get through it to the motherboard itself.  Unfortunately, replacing that connector is kind of an ordeal.  You are dealing with a heavy multilayer motherboard, and a lot of heavy high current traces.  Best option for connector removal is to break the plastic away in bits, and pull the pins individually, and then open the holes as needed with vacuum or solderwick. To get good access to the connector, the motherboard needs to come out from the main chassis. This involves removal of front and rear panels, ALL the coax cabling and pulling all the plug in modules from the unit. Then after all the module screws, you get to remove dozens of 5mm hex head screws that hold the motherboard to the diecast aluminum RF shield box.


If anyone has a badly damaged A80 board in their unit, I am offering "aftermarket" replacement boards for for these meters.  Same circuit as original, but replaces NiCd battery with a small lithium cell. Drop-in replacement for the original card electrically and physically.  PCB is high quality with gold plated edge contacts and dark purple soldermask. Asking $125 fully assembled and tested. Will sell blank boards for $45, if you prefer to source your own parts and stuff your own board. PM me for details or to order one.
"My favorite programming language is...SOLDER!"--Robert A. Pease
 

Offline elroy

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Re: HP3568B hints and tips?
« Reply #15 on: August 06, 2019, 11:12:08 pm »
I'm setting up an HP3586B that I just bought from a previous owner who cared for it nicely. Due to the well-known issue with battery leakage, at some point he removed the battery, ran a pair of wires out of the case and mounted the battery on the back.

It's obvious the battery is very old, and ought to be replaced. I understand these were 2.4v nicad. These days, 2.4v NiMH are much easier to come by. Does anyone see a potential issue if I use NiMH instead of Nicad? (I realize the HP3586B will function without the battery, it just might be handy to have the memory retained if it's unplugged sometime.)

 


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