-
Categories
-
Platforms
-
Content
Yes I reverse engineered it to a fashion, please point out errors to help me refine?How did you derive the schematic? There are numerous errors in it so determining the cause of the problem isn't possible unless the schematic is 'correct'.
Please provide a link to the original schematic.Any troubshooting tips, PCB marked 6v for VCC yet 8 volts measured. No12v on TP2???
I can't do that - I'd have to develop my own schematic (using your own hardware) to find ALL the potential issues with yours. I'm not prepared to do it on a one-after-the-other basis. We'd be here all week!Yes I reverse engineered it to a fashion, please point out errors to help me refine?
Unfortunately there is no original schematic, i had to reverse engineer and draw this myself with KiCAD, I measured voltages around the board on no 12v but that looks to rely on a Vcc of 6v as marked on the pcb, re TP2 that was a typo its just the 12v TP as is the audi typo should have read Audio. The pcb is from a Japanese novelty item called "little jammer"Please provide a link to the original schematic.
No 12 volts on test point number 2. I have to take your word for it.There's no TP2 designation on the schematic.
Why did you alter(reverse engineered to a fashion) the schematic?What would you like the schematic to do.
You say it is from an Audi device. You mean like the vehicle Audi?
Outstanding:... The direct approach...I'm not prepared to do it on a one-after-the-other basis. We'd be here all week!
It's too easy to get too involved. We all do what we can, as we can, but there has to be a limit. I can't blame/fault the OP for the way they approached this issue as people come here for help and advice without knowing 'how to ask' for it - maybe that should be a 'pinned' page that all new members should be required to read?Outstanding:... The direct approach...
On top of that... Thorough
Come on now you started it... I mean that in the best possible way!
Between you and me let's just keep this Undercovers.
Yes thats where i'm struggling a little on IC13. The component is SOT23-5 and has "504" printed on it and i've seen a photo of another board with "50B" on it, yet I cannot seem to find an ideal fit datasheet. In most datasheets I find pins 1 and 5 could not be linked together as they are in this case. I guess unless someone out there knows what it is it would be worthwhile discussing what its there to do and looking to bypass for the purpose of proving its faulty. Please endulge me here; So what I know for further testing yesterday is that R82 is boiling hot on the thermal imager, so alot of cuurent must be passing through it, so my guess is IC13 is short. I know that in order for Q19 to pass cuurent through to the collector the base must be low and therefore IC13 does that. Lets assume IC13 is powered on pin 2 (yes its not GND) is monitoring pin 3 voltage and is pulling pin 4 low. I assume then to do this its switching pin 4 to GND on Pins 1 and 5 and that there should be some internal resistance which there isn't which is why R82 is red hot. Would anyone concur? So i'm thinking of either circumventing it to prove its faulty or injecting the 6v for Vcc from the bench power supply with 504 removed. Any pointers gratefully received?If you know what regulators they are then you can figure out the voltage that should be coming from them (obviously) then you can trace the fault BACK if the voltage is missing. The input voltage must be higher than the output voltage.....
IC13 is obviously wrong as you show 8.8V on a GND pin........
There's no expectation from me on peoples time, I'm merely reaching out, to a potential body of minds that can help me yes get to a solution of a fix but importantly too share their knowledge so I learn more that i can apply to other fixes in the future. If a small number of people each give me just me 5% of this goal, i'm much more enriched than when I started from 0% no matter how slight their input and views right or wrong. Fair points made and here are my responses.It's too easy to get too involved. We all do what we can, as we can, but there has to be a limit. I can't blame/fault the OP for the way they approached this issue as people come here for help and advice without knowing 'how to ask' for it - maybe that should be a 'pinned' page that all new members should be required to read?
Stuff like adding links to datasheets, listing measurements they've already taken, advising of procedures already done etc - for most new posts we inevitably end up requesting more information - very basic information - that takes up valuable time. Many forum members will no doubt have other jobs and offer their time as-and-when (like me) but we can't be here all the time....
There is a limit. The outer limits. I'll keep an eye out. Later...It's too easy to get too involved. We all do what we can, as we can, but there has to be a limit
I will read this right now . Is there a link for that document?approached this issue as people come here for help and advice without knowing 'how to ask' for it - maybe that should be a 'pinned' page that all new members should be required to read?
Stuff like adding links to datasheets, listing measurements they've already taken, advising of procedures already done etc
Hello Bertus and thanks for cosidering and for your suggestion, yes i had a look at that one but discounted it as to low a voltage and pin2 is GND which wound;t fit the schematic. Please have a look at RN5RF50AA and let me have your thoughts?
A game of light and shadows perhaps but that transistor looks like all three pins are shorted against the heat sink.