trock703

I've found several members have fixed their odometers by replacing burned out caps on the speedometer circuit board. I checked mine to find a transistor burned out. Does anyone know if I can buy a replacement transistor and where? The transistor is circled in red in the attached pictures and has the text "P209" written on it. Thanks in advance for any assistance!

rockshox

iTrader: (3)

i imagine any normal small signal transistor would work. just trace the connections back to find out if its pnp or npn. and thats a to92 case. then you can order from mouser or jameco.

trock703

Thank you for the quick reply!

I've determined the polarity to be NPN, but there are several other properties of the transistor I don't know:

Maximum Operating Frequency
Collector- Emitter Voltage VCEO Max
Emitter- Base Voltage VEBO
Maximum DC Collector Current
Power Dissipation
DC Current Gain hFE Min

Here is a link to what I've narrowed it down to so far at mouser:
http://www.mouser.com/Search/Refine....999+4294690434


I am by no means an electrical engineer so any assistance in determining the remaining properties are very appreciated.

rockshox

iTrader: (3)

pretty sure none of those will matter in this application. the max current/power dissipation is limited by the package to a small number anyways.

trock703

I just soldered the new components in and the odometer works! Thanks so much for your help !

trock703

Ok maybe I celebrated too soon...I went out the day after installing the new components and getting the odometer to work, to find my odometer not displaying my mileage again. I pulled the gauges back out, and inspected the speedometer board very close again for more burnt out components. I do not see any signs of other bad components. Any ideas on why it was working and now it isn't?

TpCpLaYa

iTrader: (10)

probably the new transistor. I would assume if nothing else changes and it worked right when you put it in that it failed somehow. Got any others to swap in to see if it works again?

mad_7tist

it is a pretty rough pic but how are the 3 resistors to the right of the transistor?

trock703

The three resistors still look fine.

I have several extra new transistors and 6.3v 1000uF caps, I may try re-replacing those to make sure none of them were damaged during the install or maybe defective.

IMZman just pm'd me a good suggestion to go ahead and replace all the 50v 10uF cap's as well as they may have gone bad too, but not show any signs of damage on the outside. I'm going to pick some up tomorrow and try that as well, and hopefully that takes care of it.

Below is a great link to this kind of odometer problem that has helped me along the way for any others that may need it:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/just-got-done-figuring-out-how-fix-fd-odometer-599220/

IMZman

iTrader: (1)

One other semi-**** point, the OEM cap's used are "high reliability" grade vs. standard. Both are rated the same volts and uF but have differing "hour" lives...high reliability type being slightly less. And for some strange reason, they cost twice as much (.17 vs .36). The newer Nichicon series caps that replace what's one the board are the "VR" standard series (black case) and the "PW" high reliability series (brown). Probably does not make a tinker's damn...but just thought I'd throw that out there.

Also, out of curiosity...did you try disconnecting the pos. terminal on the battery?

trock703

Yeah, I hooked it back up yesterday and tried disconnecting the positive battery cable for five minutes like you suggested...but still no display on the odometer. I'm going to replace the original two components I already replaced in a few minutes and see what result that has.

Thanks for the advice on the new caps, I'm getting ready to order the rest of the caps now.

somchhir1

iTrader: (2)

ive done this for my car, and i went through 3 resistors before i got it right...the trick was that the soldering iron was heating up the inside of the resistor and it was malfunctioning...they can only hold 105 degrees so you have to solder quick....i hope this helps...

trock703

Yeah I believe that is what happened. I replaced the cap and transistor again, but this time I was extra careful not to overheat them and it is working again. Hopefully it continues to work this time.

trock703

I wanted to post a follow-up on this and thank everyone for there input. After messing around with this thing off and on I finally sent it off to Southern Electronics (http://www.carradio.com/index.html). They rebuilt a lot of the circuitry and it has been working like a charm ever since. Also their service comes with a one year guarantee and free shipping. I'd recommend them if you're ever in the market to have any instrument panel repaired.

DaleClark

iTrader: (55)

How much did the service run you?

This is one thing that is SORELY needed in the FD community is a company that can fix tachs and speedos for a reasonable fee and do good work.

I've recently tried my hand at replacing caps in a speedo with a bad odometer, and it is VERY difficult. Not only was it a giant pain in the ***, but it didn't work when all was said and done.

Dale

trock703

The bill was just under $200. The prices aren't set in stone though as it depends on what all they have to do to get it stably working, but on mine I spoke with the tech and he tested the entire cluster replacing and repairing any weak or leaking components and rebuilt part of the board. On their site they say they'll call you with a quote before performing service, but I never got a quote they just started fixing it. Not sure if it's because i wrote them a full page hand written letter telling them to BE CAREFUL with it and a couple calls asking for the status on it or what lol....just a heads up if you're trying to be thrifty make sure you get an estimated price before they start on it. Also the turn around time was relatively quick on my service. I had it back within 2 weeks of sending it off.