'91 740 Speedo Problem...Again
#1
'91 740 Speedo Problem...Again
I just followed the repair tips
https://www.volvoclub.org.uk/faq/Ele...eterRepair.htm
on replacing classic, leaking capacitors on my speedometer and it seems to work well now, except for 1 nagging problem. When I first turn the ignition on the needle jumps to 50 mph, then when the car starts it drops to zero. It will do this for the first 3 or 4 starts then it doesn't do it anymore and works the way it's suppose to. I don't know but it seems to be "charging" something - maybe the capacitors? Is there a resistor that's burned out that should mute that initial signal? Any electricians out there that might know what's happening? Thanks
https://www.volvoclub.org.uk/faq/Ele...eterRepair.htm
on replacing classic, leaking capacitors on my speedometer and it seems to work well now, except for 1 nagging problem. When I first turn the ignition on the needle jumps to 50 mph, then when the car starts it drops to zero. It will do this for the first 3 or 4 starts then it doesn't do it anymore and works the way it's suppose to. I don't know but it seems to be "charging" something - maybe the capacitors? Is there a resistor that's burned out that should mute that initial signal? Any electricians out there that might know what's happening? Thanks
#2
I replaced all the caps on my 92 740, using high quality tantalums bought from digi-key.com (electronics component vendor), and it didn't fix mine... the speed won't read above about 45mph 90% of the time, although once in a blue moon it works normally.
My understanding is there's a speedo chip that fails. You can apparently buy this chip from China (the originals were made by ITT), but I never bothered, and just relied on GPS speed when on the freeway.
My understanding is there's a speedo chip that fails. You can apparently buy this chip from China (the originals were made by ITT), but I never bothered, and just relied on GPS speed when on the freeway.
#3
I replaced all the caps on my 92 740, using high quality tantalums bought from digi-key.com (electronics component vendor), and it didn't fix mine... the speed won't read above about 45mph 90% of the time, although once in a blue moon it works normally.
My understanding is there's a speedo chip that fails. You can apparently buy this chip from China (the originals were made by ITT), but I never bothered, and just relied on GPS speed when on the freeway.
My understanding is there's a speedo chip that fails. You can apparently buy this chip from China (the originals were made by ITT), but I never bothered, and just relied on GPS speed when on the freeway.
#5
Thread
Thread Starter
Forum
Replies
Last Post