Quicky Speedo Question

[CaptRet]

Re: 1981 380SL

Pulled speedo (Electronic no cable) because odometer stopped working..........My question, what is that capacitator looking thing that plugs into the back of it. I removed it from the rear casing and it's marked 100mA 250v.

Also, my cruise is not working. The amp and actuacter are fine, from the reading I've done here, I've tried to check for a speed sensor near the speedo, but cannot find it. Is it built into the unit? Please excuse any spelling and I hope my description is enough.

Thanks in advance!!

[CaptRet]

Me again....

A speedo rebuilder called it a jumper, but since it has a 100mA-250v marking on it, I believe its a fuse. It shows no continuity... and actually cannot get any reading from it.

Again, it resembles a capacitor and plugs into the back of the speedo.

[Peter O Hara]

Hi CaptRet
The Device you describe sounds like a fuse, and 100ma would be the current rating (0.1 amp) Iv sent a pic of a Wickman fuse that came out of the SEME catalogue. you can probably get one from a TV/video repair shop. only thing is I dont remember seeing them as long ago as 1981. Maybe the Krauts really were advanced !

[manny]

Originally posted by Peter O Hara

Maybe the Krauts really were advanced ! [/B]

We still are.

[CaptRet]

Pete...

Thanks for the pix, that's exactly what it is. The parts dept. at my local MB dealer had never seen one.

Mine was blown, so I wired in a 100mA glass fuse for the time being, and my odo started working again. ( I'm not sure if it was the fuse or just the jostling of the gears that got it working).

Does anyone know for sure just what that fuse protects? Palo A**o speedo rebuilders didn't offer much info.

Pete, could you also give me the full name of that catolog?

Thanks again....John

[Peter O Hara]

Hi John
The cat. the pic came from is SEME, but its in UK.
Tel No is 01280 823434
order code is fuse666 This is for a 160Ma fuse, but will be ok for your use. You could try local RADIO SHACK shop. but come on you US guys, there must be a TV/Video repair man near you whos got a whole box of them.

[Peter O Hara]

Hi John
A Story about modern fuses.
AIWA VCR, strange fault, on playback, vision was normal, but sound was from incoming tv signal. Spent forever tracing. Eventually found that 5volt logic signal that selects sources was only about 3.8volts. The Cause ? a fuse (known as a circuit protector) gone high resistance, only about 10ohms. This fault was later reported in AIWA tech reports. Have had it a few times since, but never with a Wickman type fuse.
Happy Days
Peter

[CaptRet]

Hi Peter:

Thanks again for your help and that interesting fuse story. That would have driven me crazy also....as I usually only check fuses for continuity.

I had tried the Rat-Shack with no luck, and have had no luck with some of the small electronic shops in my area. I'll do a Google search for it next locally, and if worse comes to worse I call the UK.

Regards.........John

reading through this thread it crossed my mind that the fuse that failed might actually the wrong type - PO used whatever was at hand to get it going.
As I do not have an electronic speedo (gotta bouncy needle, though )
As the dealer did not know what the failed fuse was, maybe that proves me correct.
just my 0.02's
L

[CaptRet]

After a week of searching, a friend of a friend with a an early '82 380SL let me pull his speedo....I found the same fuse, but his tested fine. After much searching I found that the fuse is a Wickman (has a small w on it), but cannot find out what circuit it protects (cruise control???). When I get a chance, I'll pull it and see if my odo stops.

As for finding one in the US, I found one company that stocks it, but has a $50.00 purchase min. Too much to pay for a fuse.