Back in January Ken Moffet & others were waiting for a schematic from me http://forum.allaboutcircuits.com/sh...ad.php?t=48762 . To be fair, at that time we were basically tossing around ideas of starting completely from scratch.
Included in this present post is a pdf that hopefully will show enough so I can use my my lab grade soldering & desolderer & isolate the most likely cause of the rare problems that I have had with the specific board & its functions.
On two boards --- they have lost the ability to allow selections. The "off" led is on but no other outputs or leds --- even with the proper 24VAC timer load input. Hopefully some of you farther along can help me isolate the problem based on the key components. The large number of more common capacitors, diodes, resistor components that I did not show must have something to do with the 24VAC nature of the board I believe --- such as many bridge rectifiers. Hopefully, some of you can at least comment on what the most likely flow of the current or pattern that takes place based on the linked data sheets of the key components used & on what the specific board needs to accomplish & also based on the hi res pics!
Another board --- has 2 outputs #10 & #11 stuck on even when the load from the timer or bypass is not on. #10 & #11 corresponding leds are also stuck on when the board is powered on.
I did get some advice from a recent post to trace the exact connections that includes so many --- so it is really tough doing that --- since there are connections both on top & the bottom of the board. Also the data sheets are going over my head on those 4 more specialized components that I identified & provided links to the datasheets. The mediafire link on the attached pdf shows the hi def detail of the board.
http://forum.allaboutcircuits.com/showthread.php?p=388536#post388536
I don't know if "all about circuits" allows prizes to be given for a solution to a problem but I would sure be openminded about that if it would help. Normally, a board like this would not be worth saving but we have already --- including some on this forum invested some & who likes to give up too easily? Like "History Detectives" I exhausted every possibility of finding the fab shop that designed & made this board even though it was part of the "top of line" offering of a self service car wash coin box. The "good faith" efforts were all made in writing to everyone who had any previous connection or potential connection. I got a "somewhere in Northern Minnesota" but no chance of finding them or allowing them to broker for me --- apparently the installer of the equipment lost all records of the board. It seems they replaced the boards with something less user friendly --- triple decker mechanical rotary switches.
Since we have 10 of these boards we know of their extremely good quality as evidenced by --- only 3 problems over a 24 year period. The timer & bill & coin drop & front panels have already been arranged to fit with this board so you can see why we would like to isolate the component or combination of components that are giving the trouble.
There is absolutely no sign of a burn on the boards to give us a clue & the waterproofing conformal looks like new on them. The waterproofing conformal --- we will have to dab off with a q tip (Toluene) or something when we finally isolate the area based on how the data sheets are interpreted & based on normal functions that should occur. Hopefully, that will happen with some of you folks assistance &/or brainstorming. If nothing else --- hopefully --- it will be a learning experience.
Steward
Included in this present post is a pdf that hopefully will show enough so I can use my my lab grade soldering & desolderer & isolate the most likely cause of the rare problems that I have had with the specific board & its functions.
On two boards --- they have lost the ability to allow selections. The "off" led is on but no other outputs or leds --- even with the proper 24VAC timer load input. Hopefully some of you farther along can help me isolate the problem based on the key components. The large number of more common capacitors, diodes, resistor components that I did not show must have something to do with the 24VAC nature of the board I believe --- such as many bridge rectifiers. Hopefully, some of you can at least comment on what the most likely flow of the current or pattern that takes place based on the linked data sheets of the key components used & on what the specific board needs to accomplish & also based on the hi res pics!
Another board --- has 2 outputs #10 & #11 stuck on even when the load from the timer or bypass is not on. #10 & #11 corresponding leds are also stuck on when the board is powered on.
I did get some advice from a recent post to trace the exact connections that includes so many --- so it is really tough doing that --- since there are connections both on top & the bottom of the board. Also the data sheets are going over my head on those 4 more specialized components that I identified & provided links to the datasheets. The mediafire link on the attached pdf shows the hi def detail of the board.
http://forum.allaboutcircuits.com/showthread.php?p=388536#post388536
I don't know if "all about circuits" allows prizes to be given for a solution to a problem but I would sure be openminded about that if it would help. Normally, a board like this would not be worth saving but we have already --- including some on this forum invested some & who likes to give up too easily? Like "History Detectives" I exhausted every possibility of finding the fab shop that designed & made this board even though it was part of the "top of line" offering of a self service car wash coin box. The "good faith" efforts were all made in writing to everyone who had any previous connection or potential connection. I got a "somewhere in Northern Minnesota" but no chance of finding them or allowing them to broker for me --- apparently the installer of the equipment lost all records of the board. It seems they replaced the boards with something less user friendly --- triple decker mechanical rotary switches.
Since we have 10 of these boards we know of their extremely good quality as evidenced by --- only 3 problems over a 24 year period. The timer & bill & coin drop & front panels have already been arranged to fit with this board so you can see why we would like to isolate the component or combination of components that are giving the trouble.
There is absolutely no sign of a burn on the boards to give us a clue & the waterproofing conformal looks like new on them. The waterproofing conformal --- we will have to dab off with a q tip (Toluene) or something when we finally isolate the area based on how the data sheets are interpreted & based on normal functions that should occur. Hopefully, that will happen with some of you folks assistance &/or brainstorming. If nothing else --- hopefully --- it will be a learning experience.
Steward
Attachments
-
107.5 KB Views: 21
Last edited: