Transisters? Resisters? Diodes?

[TMiller]

I need to rebuild my control panel circuit board. Does anyone have a schematic or parts list describing what transisters, resisters, capacitors, diodes, etc, make up the electrical components of the control panel circuit board? This is for a 1972 25' Airstream Trade Wind. According to the service manual, if all the lights on the control panel stay on and the switches check out 'OK', then the circuit board needs to be replaced. I understand that the circuit boards are no longer available, soooo, I am going to try replacing the electrical components on the existing circuit board and see if that works. If it doesn't, I'll have to rebuild one from scratch using a Radio Shack circuit board kit. Either way, I need to know what the 'values' are of the various electrical components. I have my electronos technician bro-in-law checking his sources, but he is not haviong much luck! Any help would be greatly appreciated. Tom

[TomW]

I believe what you are looking for is a schematic diagram of the board.

The first thing you need to do is determine your brother-in-law’s interest level since he probably has access to the right electrical trouble-shooting tools. Think you can entice him with a cooler or humidor of his favorite vice?

Unless it’s a proprietary circuit board, the individual components’ (transistors, capacitors, etc.) value is usually stamped on it. You only have to have a schematic when that is not the case. A really good technician “don’t need no shtinkin’ schematic” if the parts’ values are known.

Let’s say B-I-L is interested, and determines a schematic is definitely needed. Look on the circuit board and see if the manufacturer’s name is stamped anywhere (Airstream probably subbed out the design & fabrication work). If a name is found, contact the company and see if they still have a schematic in the archives. If no name is found, there is a good chance that Airstream designed the circuit, and subbed out the fab work. In that case, Airstream would probably still have the schematic in the back room. It might be difficult, however, to inspire them to go look for it.

Work on B-I-L or dig up some dirt on him; He can fix it!

Tom

[TMiller]

Tom. I appreciate the response. A quick look at the circuit board shows the word 'Airstream' printed on it. I have yet to disconnect the wires and take a closer look. It took about an hour to individually label each wire, indicating where it came from and where it goes to (along with their individual colors) and plotting those on a hand drawn diagram. I spoke with a Jim Parrott (not sure of the spelling) at Airstream (937-596-6111, ext 7409) and he stated that they don't have anything saved for trailers that old. I would have thought they might have it on microfilm/microfiche or somewhere in their archives, however he states that they don't, and have know way of knowing where it was manufactured. It makes you wonder though, if a multi-million dollar lawsuit defense hinged on providing this 'parts list', I suspect it might become available. Oh well, that's just the cynical 'cop' in me spouting off! Luckily my bro-in-law works for Michigan State University and might be able to utilize their expertise as well. Who knows, maybe some old prof. might recognize the components and we'll hit paydirt. Again, thanks for the response. I'll let you know if we get this thing figured out. Have a safe day! Tom

[Wardinbb]

Hi Tom,

Actually wouldn't it be much simplier to purchase a new control board?
My rig doesn't have a momitoring or control panel and I've found several that range from 30.00 on up. Since you have made a wiring diagram and know where all the lines run, I would think a replacement board would be easy to install. Additionally the montitoring technology has improved where a sensor can be applied to the sides of a tank to obtain a reading as opposed to a probe that had to be inserted into the tank.
Good luck with your efforts.

Ed

[TMiller]

Ed. I would like to buy a new control board but have been told they are no longer available. If you hear of one, or an aluminum 'Trade Wind' emblem for a 1972 Airstream, let me know! Thanks. Tom

[Wardinbb]

Originally Posted by TMiller

Ed. I would like to buy a new control board but have been told they are no longer available. If you hear of one, or an aluminum 'Trade Wind' emblem for a 1972 Airstream, let me know! Thanks. Tom

Tom, I think what's not available is specifically a 1972 AS monitor panel as was originally installed in your TW. See this Ebay closed item for reference: 2489260672
I might be confused about what you mean by 'control board' but it means to me a panel that monitors and displays fresh, black and grey water tanks, water pump & water heater on/off, battery charge level and anything else you want it to say or do. Do a web search and you can have whatever you want.

Good luck, Ed

[TMiller]

Ed. The EBAY one looks pretty close to mine, especially the right half side. Mine just has a clock on the far left, an outdoor thermometer to the right of the clock and then the Ammeter, then Battery guage, then the switches and lights. Actually, all I really need is the small circuit board where the wiring attaches and inter-connects with the transisters, etc. While it would be nice to find an intact and working control board, I'n not ready to shell out big bucks just yet! Thanks for the reply, though. Tom.

[joecj76]

If the board is defective, try bringing it to a votec school and let the kids try to fix it!

[Tinsel Loaf]

Generally problems with most electronic boards are on the power input or power output sides. Control problems usually are caused by old electrolytic capacitors or tantalum capacitors however sometimes a chip will blaze out. First see if you can get any part numbers off the ic's and if they are available. If the ic's are no longer obtainable you must look for an old bord. It can be repaired. There are technicians out there that can do miracles with nothing, it just takes a miracle to find a good technician.

[McMullen]

I'm probably getting into something that I don't know anything about BUT I bought a control board from my local motorhome bussiness that tells how much water is in the water tank and how full the waste tank is and how high the batteries are and if the waterpump is running and maybe some more stuff. I havent installed it yet and do not know if I will . It cost about 45 dollars two years ago. and if you want I will dig it out tomorrow and see what the name on it is.

[74Argosy24MH]

I was playing around trying to figure what to do about my totally trashed control panel. My tanks have 4 level sensors and a ground. I hooked a 2k resistor in series with a led to each sensor, hooked 12v to the 4 leads and ground to the ground sensor. The leds lit as I filled the tank. If you have a similar setup and don't mind starting from scratch on the panel you could add a voltmeter, pump power, whatever is already there.

John

[TMiller]

Thanks John. I'll run that suggestion by my Bro-in-Law and see if it might work for me. Tom

[raebaker06]

Originally Posted by TMiller

I need to rebuild my control panel circuit board. Does anyone have a schematic or parts list describing what transisters, resisters, capacitors, diodes, etc, make up the electrical components of the control panel circuit board? This is for a 1972 25' Airstream Trade Wind. According to the service manual, if all the lights on the control panel stay on and the switches check out 'OK', then the circuit board needs to be replaced. I understand that the circuit boards are no longer available, soooo, I am going to try replacing the electrical components on the existing circuit board and see if that works. If it doesn't, I'll have to rebuild one from scratch using a Radio Shack circuit board kit. Either way, I need to know what the 'values' are of the various electrical components. I have my electronos technician bro-in-law checking his sources, but he is not haviong much luck! Any help would be greatly appreciated. Tom

If you take the panell cover off the circuitry is attched to the cover. there are wires and a circuit board there. Unplug the wiring and plull the long temperature sensing lead out , But go under the trailer and find the temp sensor in a tube and attach a string so that you and pull it back down when finished. Look at the circuit board and you should be able to read the transistors (used as switches) and find a replacement. I doubt that RAdio Crap will have them. Get soeone who does electronics to find them or substitutes. put them in and the resistor if burned and re install the system. Becareful as the plastic may be brittle and my break. Remember that the meters can los their ability to read fully. The magnets in the meters can lose their strength.
If you have trouble with the transistors, you can mail me with the info and I will try to help. I have a friend who needs my help in this manour.

Being a wonderful and knowledgable (and if you don't believe me just ask me)

Rae
rbaker@nas.net....till OCt 29th and then look for me from my Florida E-Mail addr. I will be on here from there.