Basic Board Help

[jamesmcuk]

Hi

I need a bit of help with this board. This board is one of two that work similarly. One which is working detect a printer cart being inserted when a bit of dark plastic goes between two sensors. The second pictured works the same way but detects if ink is in the cartridge through a window in it. Anyway. Its not working but I don't really know how to bypass it.

One the back of the board represented by the colours on the pic are the sensors each colour is the pair for each cart. I could do with help trying to understand how to solder this up to make the board think the sensor can not see the other i.e. there i ink in the tank.

Also what would NT1 be?

Thanks in advance

James

[juliadream]

Re: Basic Board Help

It has the look of a cap about it to me.. but it could be pretty much anything with 2 connections.. voltage limiter.. transient suppressor..
Resistors that size tend to be black and have numbers on them.. but not always.. and it depends with smd stuff if it's even the right way up.. what's on the other side of the board and where do those traces go.. Have you thought to have a dig into t'internet and see if you can find the schematic for the printer somewhere?

Because that pair of traces are fatter than the others coming from the connector they look like a power supply rail and probably ground.. so a cap makes sense.. Have you stuck your meter across it.. hopefully you will get o/c or very high resistance.. depends what those traces are feeding on the other side..... there are through board vias so no doubt there is print on the other side too..

As for the sensors.. phototransistors or 1/2 an optocoupler.. look up their numbers and find out the resistance when in light and their resistance when dark.. obviously the ink is blocking light in some way.. so the "dark" resistance is what you need to swap them with.. or try sticking some black tape over them even.. hahaha.. all good fun..

One thing to note.. see all that corrosion looking crap all along the bottom traces?.. could be causing a low resistance leak between those tracks..