IEC F54A Function Generator Repair - Page 1
Forum section: electronics / repair

author: Frankentronics
author_rank: Regular Contributor
timestamp: June 05, 2020, 01:27:02 am
content: Greetings,I just bought a function generator on eBay, model IEC F54A.The seller did not disclose that the unit was not working. It powers up but does not produce any meaningful signals. I only got some noise out of it, when I zoom in on my scope, and at times it does produce some kind of jagged oscillation, but I the frequency knob does nothing to change the frequency. Even so, it doesn't actually produce this oscillation every time.Given the fact that I am unable to find any manuals for this unit, how realistic is it to fix it? Should one even bother or are the parts going to add up to more dollars than buying another one?I paid $95 with shipping.Any thoughts would be appreciated.Thank you...

author: Frankentronics
author_rank: Regular Contributor
timestamp: June 10, 2020, 03:11:28 am
content: The seller was very nice and gave me a partial refund. So, it ended up costing me $25 to keep this unit, so that I can try to fix it.Hopefully with some help from members on this forum I'll be able to fix this unit. It is a very nice piece of equipment and it would be a real shame to see it go to waste.I made a couple of preliminary diagnostics videos. But basically, I can get only one type of signal out of the unit, only when the function selection switch is on sweep position. To be honest, it would take longer to read through a detailed description than to watch the videos that I've recorded. And I guess I can keep making videos, when needed, in addition to posting progress reports in this thread.In the following video you see me do some preliminary tests.https://youtu.be/3Tj3PfYUIIgIn the following video I tested the power supply section.https://youtu.be/ZAxnDHOlPHkWhile I was recording my second video I noticed some oxidation on the leads of on of the socketed IC's.Could this be at least part of the problem? I didn't pull out this IC yet, as I don't know if that might cause more problems, as I don't really have a plan how to clean the oxidation from the socket.Any help fixing this unit would be greatly appreciated.Thanks...

author: picburner
author_rank: Frequent Contributor
timestamp: June 10, 2020, 08:06:45 am
content: I have not found any free manual on the net but I have found who sells ithere, you can ask him if it includes the schematics.

author: Frankentronics
author_rank: Regular Contributor
timestamp: June 10, 2020, 12:46:43 pm
content: Oh, fantastic!I just sent the seller a question, but I have a feeling buying this manual will be the first next step. I'm sure it does include the schematic.EDIT: Seller replied. It does include a schematic, so of course I bought it.Thank you very much for this link.Once it arrives I'll scan it so I can post it here.Thanks...

author: picburner
author_rank: Frequent Contributor
timestamp: June 10, 2020, 06:08:40 pm
content: If the scan is too large to post here you can post it onDidier's website, all my manuals have gone there.

author: White Dragon
author_rank: Newbie
timestamp: August 15, 2022, 11:02:09 pm
content: For anyone seeing this reply, the repair of this unit is often as simple as re-seating all the components that are in sockets, and sometimes all the connectors in the unit. Do it with the unit unplugged. If a simple "U" shaped IC puller with tips folded to fit under the chip works well. If not available, you can also use a flat-bladed jeweler's screwdriver. You don't usually need to take the chips completely out of the sockets -- just lift both sides up about 1/8" then re-seat the chip. While it is possible to straighten bent IC leads, it's better to take care not to bend them. Good Luck!