Agilent 6626A quad power supply teardown

[free_electron]

That switch is nothing special. it is made by Preh.

[TAMHAN]

free_electron to the rescue. Now it is but a question of meeting the minimum order at Farnell, RS or another distributor of choice!

[hendorog]

That switch is nothing special. it is made by Preh.

Thanks for that info. I was hoping to get the same switch, but if it doesn't work out I'll just find something generic.

[hendorog]

Well the local agent has responded with two options:

1. The replacement switch for $77USD. Cost on Find a part is $9.48
2. An alternative part they have in stock for $34 USD. Cost on Find a part is $5.59

Hmm. No surprises there.

[TAMHAN]

Makes me feel like paying the findapart fee

[hendorog]

Makes me feel like paying the findapart fee

Yeah - if only they would just shut up and take my money 

[TAMHAN]

Hendo, I will prolly do an ASSCRATE of an order on Tuesday from Farnell. But I am not sure if all the caps I need for my scopes will bring me above 25$, and I still didnt get my trade account so 

If the part is available from there, I will gladly gang up with you on it. So you let me know the number, and I check if I can order it sensibly. If yes, as soon as I get it, I stick it in a slovak post first class letter and send it to wherever your HendoNess might live.

[nctnico]

@hendorog, maybe worth emailing the local agent... you may be surprised.

I say that as I've been through the same as you to some extent, needed a front panel replacement for a power supply I bought used on ebay.
Found the part in their website (well, didn't find it at first but asked for help via the feature in their search page, and next day received a detailed email with pictures from an engineer who had identified the part I needed) and then was informed I could not order it directly as I'm not in the US.

I have a similar experience with the support from HP/Agilent/Keysight in the NL. Unfortunately the part I needed was no longer available but still great service.

[hendorog]

Hendo, I will prolly do an ASSCRATE of an order on Tuesday from Farnell. But I am not sure if all the caps I need for my scopes will bring me above 25$, and I still didnt get my trade account so 

If the part is available from there, I will gladly gang up with you on it. So you let me know the number, and I check if I can order it sensibly. If yes, as soon as I get it, I stick it in a slovak post first class letter and send it to wherever your HendoNess might live.

Hehe, great post! 

I'm in the same boat and have been building up a shopping cart - and I know it will add up to enough to make the free shipping at digikey (ouch!)
We have our summer holidays now, so it will be a while...

So thanks for the offer, I appreciate it, but I'll order it a bit later when I have time to make use of it.

Cheers!

[TAMHAN]

No worries, Hendo. I know that feeling just too well...swamped with work here.

[Bud]

You need some high power cooling:

I have a 6622A and the fan is noisy (Papst 4600X). What is a proper method to oil fans that have Sintec bearing and what oil/grease to use ?

[SeanB]

Peel back the label, and use a needle to pop out the rubber seal if it did not come off with the label. Grab some synthetic engine oil ( Mobil one or equivalent 0W30 engine oil) or some straight SAE 15 mineral oil, and place a few drops on the bush. Leave with the bush uppermost for an hour or two, so it soaks down into the bush, then fill up level with the top of the bush, pop the rubber seal back on then stick the label back down.

If the rubber cap is still very flexible ( press down on it to see if it flexes under the label) then do not peel the label, just use a small needle on a syringe to inject 0.5ml of oil into the space under the bush.

[Bud]

I ended up with sewing machine oil, which is a clear low viscosity oil. The fan though did not have a rubber seal. Under the label were two screws, after removing which the fan split to two parts and the one with the motor assembly had a metal cup at the end, so I put a few oil drops there.
The power part with heat sinks of my 6622A looked different from OP's 6626A, pics attached.

[SeanB]

They don't want you changing those output transistors for sure, with that ceramic hybrid interconnect. Probably also has the ballast resistors in there as well, to save board space.

[SharpEars]

All right, which one of you bastahd snipers won the auction on the HP 6626A unit on eBay? Nice bidding war on that one.

I sniped won the Agilent one and there's one more HP unit ending tomorrow from the same seller.

[PTR_1275]

I know I am bringing up a dead thread, but I couldn't see much other information on the 6626a in the forum.

I have one that I purchased a few months back. I haven't had time to do much with it until recently. Channel 3 is getting abnormal over voltage errors.

The OVP is set to 55v. The power supply output voltage is pretty bang on, but if I go above about 15 volts, it shuts down with a OVP.

I have been reading through the service manual and the first thing to check is U327. On the boards I have, U327 has been replaced by a hybrid module fitted over where U327 would normally go. There are a few header pins which I am assuming are the required test points, but I cannot find any information on what pin is what.

The copy of the manual I have is from the keysight website and was printed September 2001. My unit doesn't have a serial number on it (I thought I was going crazy, but can't see a serial number or even evidence of there being one), there is a sticker on the metal case (under the cover) that says 6626A 20000342.

Does anyone have a copy of a newer service manual, or know what the amendment would be?

[TAMHAN]

Hello,
all I know is that the unit switches its power train at 15V or so.  Maybe check the two regulator threads.

Tam