Please help, Component Identification.... - Page 1
Forum section: electronics / beginners

author: danamaniac
author_rank: Contributor
timestamp: August 21, 2022, 04:36:42 pm
content: Hello everybody, I been on this great forum many times but this is my first post. I have a Link KnockBlock on my desk, its a device for listening to engine detonation. I need to identify this component so I can test it and find the fault. I already suspect it is this part but if i dont know what it is I cant test it.The markings are mostly rubbed off, I think the top line says 348J, it is an ssop8 chip.Please help me I have searched google for hours.If anybody can give me some guidance or tell me what this thing is I would be so happy and grateful.Cheers

author: inse
author_rank: Super Contributor
timestamp: August 21, 2022, 05:04:52 pm
content: Have you tried cleaning everything with IPA?Maybe in wet state, other details show up.Are the other ICs grinded off as well?

author: danamaniac
author_rank: Contributor
timestamp: August 22, 2022, 01:57:28 am
content: Its my stupidity, there was lacquer on the pcb, i ever so gently scratched it off but took the identification markings with it aswell.

author: danamaniac
author_rank: Contributor
timestamp: August 23, 2022, 04:47:27 pm
content: Please somebody must be able to help with this?

author: Andy Watson
author_rank: Super Contributor
timestamp: August 23, 2022, 05:07:12 pm
content: Quote from: danamaniac on August 22, 2022, 01:57:28 amLooks like the markings may still be present but are obscured by scratched lacquer. Try IPA to remove the lacquer. If that fails, try something a little more potent like acetone.The other chip on the board appears to be unmolseted - does it have a legible number?Given its position on the PCB I would suspect it will be an op-amp, or possibly a dual op-amp.

author: danamaniac
author_rank: Contributor
timestamp: August 27, 2022, 01:17:58 pm
content: Thanks Andy, i am pretty sure the top line reads 348J, i can make out that much. That photo is after acetone and a cotton bud cleaned it.The bottom line is not legible.Is that enough to identify the component?

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: August 27, 2022, 01:25:24 pm
content: I cannot help with the chip ID. But does this device act as a DSP or an amp? I suppose you could use it while driving but we always just used a bit of timber to the ear. Blokes that worked on Jags were pompous and could afford stethoscopes.

author: Andrew_K
author_rank: Contributor
timestamp: August 27, 2022, 10:22:44 pm
content: Quote from: danamaniac on August 27, 2022, 01:17:58 pm"348J" doesn't return much on google or octopart.It's certainly not the LM348J, as that is a quad opamp. There is the OPA348, but TI doesn't make a version with the "J" suffix.It looks like there could be additional text, obscured by the scratches.Try putting a piece of clear scotch/sticky tape over the top. That may smooth out the surface scratches, leaving behind the deeper letter indents. If that doesn't work, try putting a drop of water over the scratched part.Hopefully that makes the bottom text legible. Otherwise, pretty much impossible to say for certain what the chip was.What product is this board from?