EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: bingo600 on April 06, 2014, 03:07:53 pm
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I just got my first my first Powermeter :)
A used HP E4418B EPM Series Powermeter , with a HP 8481A sensor.
The meter is in a very nice condition , and have Opt1 (Battery Pack) installed.
As i knew the sensors are easy to damage i asked a very RF knowledgeable and kind person named Dave if he had a pair of tips for testing it at the sellers place. (Dave is actually a friend of user KJDS).
Dave ansvered many of my newbie questions regarding the powermeter, and he was kind enough to come up with the attached list of steps, to verify correct operation of the meter and sensor. Once again thank you Dave.
I went to the seller ,a kind radioham in Denmark. And when i came the meter had already been powered/warmed up.
We verified the meter and sensor, and all went ok.
But when i came home i was greeted with the following PON selftest message: Ram Battery Failed
The meter went on to normal operation , but still showed : ERR Power-up H/W Err (Pict 33)
I found out it couldn't pass "Confidence test" due to having lost the sensors Cal-data , so i had to recalibrate the sensor.
That's not difficult , but a bit annoying.
But besides that , the meter functioned fine.
Continues ...
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Well i still hadn't seen the bugger inside , and a battery change would be a nice way to learn the beast to know.
I had downloaded the service manual , and found the HP-PN for the battery BT1
BT1 Lithium (RAM) Battery - Agilent PN: 1420-0338
Normal PN: BR2/3AE2SP
This one will also work (I used it in my HP3478 DMM)
SANYO / FDK CR17335SE - 2/3A m CR17335SE-3PIN
http://www.batteribyen.dk/sanyo-fdk-cr17335se-23a-med-loddeflig-1-stk-3112 (http://www.batteribyen.dk/sanyo-fdk-cr17335se-23a-med-loddeflig-1-stk-3112)
That was great news , it's the same battery as i used for my 3478 DMM. And i had one in the drawer.
Pict 16,23,24 is the old battery still in the meter.
I fought quite a bit getting the old battery out , as the service manual mentioned that it had been fastened with silicone.
They mentioned that one might need a Scalpel to cut it free , but i as i was to lazy to dismantle the whole box. To get the A10 (CPU) board out. I decided to change it with the PCB still in the box.
I used a manual vaccumpump ,and sucked the holes as empty as i could. But i still couldn't get the battery free.
I then decided to break away the soldertabs from the battery. That was quite easy , just using a little screwdriver to break the weldings. Now i could get the battery free , well actually the bottom plastic and silicone stayed on the PCB.
I'd use a scalpel next time i encounter a silicone glued battery of this type. And cut a thin line in the plastic.
Now it looks quite abused - See Pict 35,36,67.
As i read HP recommends a battery change every 3 years,i decided to solder another type of the same battery in.
I had one in the drawer with just 2 pins , and a bit longer leads.
I left the battery floating a bit from the PCB , to make it easier to cut the leads on the next battery change.
Ohh :palm: the observant reader will notice i used to little heat when soldering the minus on the battery , but the meter is going to sit on my shelf wo. any vibrations etc. So i'm lazy and won't reopen it to redo the joint.
Maybe one ought to photograph all the pcb's , it's quite revealing.