Detach display board ribbon cable on 34401a from the connector on main PCB? - Page 1
Forum section: electronics / testgear

author: DefinitelyNotLarryEllison
author_rank: Contributor
timestamp: March 04, 2019, 02:11:48 am
content: I'm trying to detach the front panel/display board from the main PCB in my 34401a. Does anyone know the correct technique for getting that ribbon cable out of the connector/header without destroying my meter?I've read the disassembly "instructions" in the repair manual, but they are completely unhelpful. There's even instruction on the inside of the meter that says something like "Push Down." But everything I've tried completely feels like I'm going to break something.I've searched these forums and the internet in general, but come up empty.BTW, I'm already quite certain it's something really stupid and totally obvious to everyone but me...

author: mr.fabe
author_rank: Regular Contributor
timestamp: March 04, 2019, 02:35:30 am
content: Try this as your lightly pulling out the cable...

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: March 04, 2019, 06:10:27 am
content: Exactly, push down on the tab firmly (if you push too lightly, it would appear as if it is not a push tab), it will release the cable.Same process to reconnect, good luck.Quote from: mr.fabe on March 04, 2019, 02:35:30 am

author: mr.fabe
author_rank: Regular Contributor
timestamp: March 04, 2019, 06:34:10 am
content: A view from the side...Sent from my Moto Z (2) using Tapatalk

author: DefinitelyNotLarryEllison
author_rank: Contributor
timestamp: March 04, 2019, 08:07:09 am
content: Thanks to you both - I'll give it a(nother) shot!This is exactly one of the things I had initially tried, but the PCB was flexing mightily and I started to get very nervous... Maybe I should try supporting it from the bottom as I push from the top.Thanks again.

author: floobydust
author_rank: Super Contributor
timestamp: March 04, 2019, 08:36:30 am
content: DON'T PULL HARD ON THE RIBBON CABLE, press the latch release and it easily comes out.The connectors are obsolete, if you wreck one it's a PITA to change over to another type of connector.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: March 19, 2019, 03:24:12 pm
content: I just had a meter with one of those being abused. Somebody have tried to push on the release bar with a screwdriver and it obviously slipped. Few traces got damaged and the display didn’t work anymore.Anybody knows the good “replacement” connector with correct pitch to replace broken one with?

author: vtp
author_rank: Regular Contributor
timestamp: March 19, 2019, 09:40:20 pm
content: Quote from: Ordinaryman1971 on March 19, 2019, 03:24:12 pmMolex 52147-1210, Mouser part no 538-52147-1210

author: sampler1
author_rank: Regular Contributor
timestamp: January 31, 2024, 02:58:38 am
content: well, Sorry for the delay But I have been in a far far away land for awhile.Turns out the conector was broken and I did not do it.. I manually pressed each pin and I was able to release it and the Flex cable 2mm 12 pin .Each pin has damaged ends. I am thinking of replacing it .Would anyone know a good replacement. I ordered from Mouser the Molex and a big thanks for that.ThanksPS: if anyone was wondering why I wanted to remove the Flex. It is because the 2 wire and 4 wire resistance values were jumping all ove the place. Problem is The Flex cable and conector. Seems to be a common issue.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 31, 2024, 11:35:28 am
content: this display flex cable "strand" is very rigid, it doesnt tolerate flex moves for long ....and sometimes the strands stick inside the connector pins, it get very difficult to move / remove the flex from the connectoreven pushing very hard on it, does not release all of them, i had to wiggle a bit ...you have multiples voltage who goes in it for the vfd board and the mcu ...

author: floobydust
author_rank: Super Contributor
timestamp: January 31, 2024, 07:12:41 pm
content: Quote from: sampler1 on January 31, 2024, 02:58:38 amThat connector has nothing to do with 2W or 4W - it's strictly for the front panel board which is display and keyboard.I would say the relay/switch or another connection is oxidized and handling the board affects that. Don't go on a goosechase.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 01, 2024, 02:28:12 am
content: front rear switchk102 relay problems ...

author: sampler1
author_rank: Regular Contributor
timestamp: February 03, 2024, 01:18:30 am
content: One way or another the connector needs to be replaced.After desoldering I seen in what bad condition it is in. After it is replaced Ill take a look at that relay.The reason I looked at this is when moving the ribbon cable that 2/4 ohms would work then not work? hummmmConector is on order.Ill let you all know

author: coromonadalix
author_rank: Super Contributor
timestamp: February 03, 2024, 03:26:21 am
content: for sure this flex cable will send commands from the front panel to the meter circuit, say in a master slave configuration ...remove the front panel, the meter will stay dumb ...some reported in the past some zenner failures and or capacitors failures, on the front panel pcb ....if you have the old unobtanium nec vfd drivers, they may or will leak on the vfd segments over time ... wich mean the meter can not be repaired on the front panelif you have the latest vfd board you're luckynormally you had some Hp Agilent notes about the front panel board vs the serial numbers, and FW versions