I would guess you have already looked through the FAQ's and found the section on failed speedometers:

https://www.brickboard.com/FAQ/700-900/ElectricalInstruments.htm#Speedometer_Failures

There is a hot link there to Overseas Speedometers (https://www.speedometer.com/)

Several years ago I posted in this forum about my contact with Overseas Speedometers with an inquiry about repairing a failed speedometer in a 1991 740 with leaking/failed capacitors. The nice/timely reply from them said that yes they had repaired them in the past but no longer did. Apparently they had had an employee that accepted the challenge of removing the old capacitors and cleaning up the board that had been damaged due to the leakage and sometimes had good results. Because of the amount of time involved and mixed results at the repair attempt they no longer accepted those speedometers for repair. I looked for my post but was unable to find it even with a Google advanced search. you might contact them to see if they can provide any leads for a repair.

The other approach is to source a 1993-94 940 cluster and swap it into your 1991. The speedometer will work fine without any alterations. However the gas gauge won't register.

The work around on the gas gauge is either swap out the sending unit in the gas tank or alter the circuitry in the cluster. I worked with another brickboarder on the necessary steps and then wrote it up. I think it might be in the FAQ's as sort of an addendum. I also must have it on my harddrive somewhere but off hand I'm not sure. If the cluster work around is of interest to you let me know and I will organize a search.

EDIT:
The search was successful. Here are two links that might be helpful:

https://www.brickboard.com/FAQ/700-900/ElectricalInstrumentClusterInterchangeability.htm

https://www.brickboard.com/FAQ/700-900/ElectricalInstrumentClusterInterchangeability.htm#FuelGaugeClock

Randy
--
Any twenty minute job is just a broken bolt away from a three day ordeal

Thanks, I've been at this for a long time and read all the remedies, etc.
I'm sure that a shop exists somewhere capable of replacing the leaking diodes; certainly there are also other brands of that vintage suffering from this failure. As far as interchangeability, the later years are a little better but not much. Yes, the 1991-2 are the worst but I wouldn't swap clusters for the hope that the speedo would perform better.

I understand that you are apparently not interested in swapping out clusters.

However your comment "the later years are a little better but not much" prompts me to share my personal experience:

I have two 1994 940t cars. One has 318K while the other is at 127K. They both have the original speedometers. I have swapped 93/94 clusters into three different 91/92 740's. Two of those have added over 100K miles since the swap and continue to register flawlessly while the third one is a garage queen. The 93/94 clusters are quite robust.

If you happen to find someone to repair your speedometer I hope you will return and share your experience with us. Good luck.
--
Any twenty minute job is just a broken bolt away from a three day ordeal

You may be correct about the speedos after 1992 lasting better. Come to think of it I have not had trouble with the 940s I have owned after the 1992 MY. The problem is that I had many at the same time which meant that none got driven much while with me. The 1991-2 740s and 940s are the problem... same as the headliners which starting with the 1992 models are much better lasting.

Many years ago I attempted a repair on the cluster from my 91 740 for an erratic speedometer I meticulously dissected and soldered in all new electrolytic capacitors. That did not work. I observed that the leaky capacitors leaked all over the terminals of the Integrated circuits ( ICs). Though I have no definitive proof I suspect the ICs might have shortened out. I replaced the entire cluster with one from another car , suspecting it may have been from a 940. The clock adjustment is different and the gas gauge works backwards. I still have the old one.

This may not be a help - or maybe it will. A few months ago I looked into having my 245 V8 conversion's tach converted to read for the V8. I did a google search for automobile instrument repair and one of the first places to pop up (somewhere in the mid-west) said they could do the job--about $100. I thought for sure I'd written out a note with the name--but just can't find it. - sorry - Dave

I can't help with a commercial shop, but tedv sent me two almost 10 years ago which I successfully repaired in my shop and returned to him. I was thankful for the opportunity to see what happens to these 740/940 Yazaki units. This corroding leakage has no equal in any other brand or product I've seen.

The benefit to me was being able to write it up: http://cleanflametrap.com/speedo7.html

(tedv -- if you still have my address you're welcome to send it. If not, write me brickster at cleanflametrap dot com)
--
Art Benstein near Baltimore

How come nothing rhymes with orange?
What? Nothing doesn’t rhyme with orange?

Hi,

I’m surprised that no one has responded to your post.
I’m a totally 240 person but there some people still rolling around in the 700 series but you have to know the 700 and 900 series have different speedometers made in Japan, i think from the name I have seen on the back of them.
Since it’s a 1991 that puts in the age of when the 240s were still being produced.
I see that you are saying you are from Oregon state so at least you are on the west coast.
I have dealt with the Wagonmeister down in the mid state of California, Near Bakersfield or Lancaster Ca.
He is into refurbishing Volvos and has a collection of speedometers for the 240 series clean and repaired himself I think?
On his web site he lists a service for them but he might have other models of things as he occasionally details out other car for other clients.
He details every inch of his project’s vehicle. At least every inch that can be reach or seen and the cars are absolutely road worthy. He has made a reputation doing it for $$ but if you want it done right expect that.

His web site is chocked fairly well with products he sells.
He is very knowledgeable since he does refurbishments so that goes in hand knowing people and most repairs of course.
I would contact him at his web site Wagonmeister.com. Email or by phone he responds to both.

Another persons web site is Dave Barton.com. The flying moose as I recall.
I was told that Sweden has mountains and moose. It is one reason the Volvos 240 were tough and large enough to get in and out of. That is, when compared to the Japanese cars of that era.
The Swedes are husky people in size and strength so it suited Americans to consider downsizing from their land yachts of the previous decades.
About 2 million cars were sold of the earlier series of 50 years or so of building them.
They stayed European until the break out of Peugeot and the demise of Saab/GM. A little TOO different of style and configurations for the American market, IMHO.
Helps explain how there an early model Volvo following today.

BOTH are worth a shout out! 😀. It’s your cab.

Phil

Merry Xmas Phil and All,

Aside from a salvage yard pull that might be an option,

here's the Dave Barton link that Phil noted

https://www.prancingmoose.com/740-odometer-repair.html
(That includes speedo)

Bill