Old Zener Identification - Page 1
Forum section: electronics / beginners

author: Bamber1_1999
author_rank: Newbie
timestamp: May 02, 2025, 10:54:15 am
content: Can someone identify the part in the image for certain? Two were in a power circuit for an old panasonic video controller; one shorted and hence, the empty spot. Diameter is 1.6mm, main body length is 2.3mm. I would prefer not to remove the still working (i believe) part to test it for the moment. I have been searching but I haven't seen anything similar. Stripes are red, red, blue so 22V? Can you recommend a replacement part? Many thanks.

author: Andy Watson
author_rank: Super Contributor
timestamp: May 02, 2025, 01:22:18 pm
content: It is unlikely to be 22V zener. The colour codes might represent part of an identification number, like say 1n622, or they could particular to the diode manufacturer. The safest action would be to remove and test the remaining diode.What is the model number of the video recorder? Have you tried tracing the circuit that surrounds the zener - it may give you some clues as to what voltage is expected.

author: madires
author_rank: Super Contributor
timestamp: May 02, 2025, 02:11:45 pm
content: Hard to tell. Vishay uses a blue band for mini MELF diodes to indicate a Zener diode (and the cathode).

author: Bamber1_1999
author_rank: Newbie
timestamp: May 03, 2025, 03:07:54 am
content: Thanks for the response. The controller, not recorder, is a Panasonic VL-V754 used for switching between hardwired cameras in a building. I'll see what I can do about tracing the circuit.

author: fzabkar
author_rank: Super Contributor
timestamp: May 03, 2025, 03:31:06 am
content: MAZ4062, 6.2V Zener could be one possibility.https://www.digikey.de/en/products/detail/panasonic-electronic-components/MAZ40560MF/1131938https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/853/MAZ4000_Series_Rev_Nov_2011.pdfNotice the coloured band on the lead. That denotes a Zener.

author: floobydust
author_rank: Super Contributor
timestamp: May 03, 2025, 03:32:49 am
content: It's a Japanese zener diode.Marking red-red is a 22V part. Blue is A rank.I'm wrong- it's not 22V but more like 6.2V because the cathode end is the blue bandLook at PanasonicMAZ4000series 0.37W like MAZ4220 22V.BiggerMAZ7000series 0.8W, not the same size I'd guess.

author: Bamber1_1999
author_rank: Newbie
timestamp: May 03, 2025, 09:17:02 am
content: Thank you so much! According to the datasheets and the info on Digikey, it looks the same. Digikey lists several substitutes including 1N4691, 1N4460 1N5234A etc.https://www.digikey.com/en/products/detail/panasonic-electronic-components/MAZ40620MF/1131939For zeners, what key characteristics need to be considered for replacement parts? Obviously, the breakdown voltage. Max power?

author: madires
author_rank: Super Contributor
timestamp: May 03, 2025, 02:00:38 pm
content: Yes, wattage is important too. It also affects I_Z.

author: Bamber1_1999
author_rank: Newbie
timestamp: May 04, 2025, 09:01:35 am
content: Thanks very much!

author: Terry Bites
author_rank: Super Contributor
timestamp: May 04, 2025, 11:09:18 am
content: A bit of reverse engineering might shed some light on this.Maybe post a drawing of the circuit schematic adjacent to the Zener.Can you identify the controller ic?Is the Zener part of the controller ic supply? If not close this reply!It often is so the ic specs will give you a clue to the aproriate value.A 22V Zener would not be unreasonable but check the controller maximum input voltage.

author: Bamber1_1999
author_rank: Newbie
timestamp: May 05, 2025, 03:53:25 am
content: Quote from: Terry Bites on May 04, 2025, 11:09:18 amWould love to have the time to trace this out fully but unfortunately, my hands are full at the moment.I replaced the part with a 6.2V zener that I had around (one of a cheap zener set bought on ebay, I think) of which I tested to make sure it could operate close to the MAZ4062 specs, along with a blown A1878 and a fuse, as well as resoldered all joints due to there being fatigue cracks everywhere. It looks like they skimped on the amount of solder used, everything was wobbling. The unit powered on and appears to be basically functional. Reverse voltage on the zener and the other beside it was 5.5V. I'll check some suspicious caps later on and get a proper spec'd zener but for the moment, I'm happy.Many thanks to all for your valuable time and input. It helped a lot!btw, can this issue be marked as closed? Can't see a way to do it.