348 Speedo Burned Internals

The CQ949 is definitely a PNP transistor and is used in an Alfa Romeo 33 speedo only with a different marking R030 which again doesn't mean anything as to correct known types.

 

Further to my posts above I have attached pics which show the board with the 92693 chip
which shows that pin3 is not connected and as such cannot be equivalent to CA3140 which has the pin as an input to the op amp.
The pics also show the boards use two transistors one with a configuration of EBC and the bigger transistor both PNP's has a configuration BCE looking from the front. The large transistor has not been identified as yet.

The board show the pin 3 arrowed with no connection and the feedthrough arrowed also has no connection
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

The huge difference is only the interface IC MC14024 to the pickup which is a different IC on the Alfa and is on a separate board.
You cannot have two IC's with the same part number with different connections.
I have swapped the CA3140 for the 92693 and it does not work ,Have you? If not try it and then you will prove it to yourself.

 

According to the Alfa 33 speedo, what year (87,88?) can i find the 92693??

 

Still any kits available? or atleast the 925693 & BDB02C

 

I have an F40 with a speedometer problem. It uses the same IC 92693. What year of the Alfa 33 uses 92693?

Bought a speedometer from 1986 that have another IC.

 

Great thread and I’ve learned a lot from it. When I took delivery on my 94 348 Spider, the speedo wasn’t working. FoA has replaced the sender on the transmission during the major and they had fixed a break in the harness.

My board had a barely visible cooking at the same spot many shown here (attached photo).

I did secure a used one last year and swapped it (it works) but looking to fix this and likely keep it as a spare.
Image Unavailable, Please Login


Sent from my iPhone using FerrariChat.com mobile app

 

Fixing mine a well, does anyone have a lead on a 92693? I have an order in from a source in China, but its been 2 weeks an the tracking number has not been picked up yet.

As for what the 92693 does, my EE friend has figured out its comparing the input signal to the output from the odometer, thats why there are 3 wires to the odo, its a sensor to close the loop between input signal and speedometer indicated speed.

 

Deliveries from China (even to me in Malaysia) have always been very slow and especially now with Covid. It may easily take 1-1.5 months.

There is no datasheet for the Harris 92693 chip. Some suppliers claim that it is equivalent to Harris CA3140 but this chip, although in the same package, appears to have different pin arrangement. Otherwise, CA3140 is an operational amplifier (see attached datasheet).

 

From testing the CA3140 is functionally different. My EE friend has modeled the complete board in math and I had provided him that datasheet (pretty sure it was linked earlier in this thread) and it did not fit the circuit layout of the board. I have not put it in the car yet, but all the components on my board (non surface mount) have been replaced, just like Mike did. I am highly confident that I need the chip, as all the components tested within specification after they were removed from the board.

 

Yes, this is the correct chip. The price is in Turkish Lira but it was translated to "US $" without conversion of the amount. It is about USD 16.

 

I had sent a request through some supplier bidding site in china, and a supplier found me through that. DHL tracking says my chips will be here Friday, fingers crossed...

Previous supplier i had found had two weeks doing nothing, when I asked when they would ship the cancelled my order and refunded my money.

 

Thanks for the update, Matt.

Would you have details for your supplier? That Turkish website looks too hard to run.

 

It ended up being the shady chinese site linked earlier. I'll confirm once the chips arrive and are the correct chips. English is def not the preferred language. If anyone state side needs a chip, I have 10 ordered (I hope) .

 

Feel accomplished, was too expensive and took time, but I am feeling victorious! I have 8 spares for sale if people want to save the time, risk and hassle. Pm me. Honestly not making profit here. $20 per chip and $5 shipping if i can help anyone the brotherhood out... Image Unavailable, Please Login

 

are the speedos modular in that one could purchase a used one and swap the boards over?

 

Yes, you could. it just unplugs.

 

I purchased a used speedo and was going to swap the boards to keep the original odometer and found that:

- plugs are different internally
- odometer gearing is different

Not sure if the used one that I purchased was previously serviced (rebuilt), but the board layout is visually identical.

I am looking to rebuild the original and hold onto it as a spare.


Sent from my iPhone using FerrariChat.com mobile app

 

Ahh there was a 2.5 and 2.7 version and a US and non US version and a mix of those. I bet part numbers are often wrong on the used market.

 

was it another 348 speedo? All the plugs on the boards posted on this thread have been identical to mine. My "rebuilt" board below
Image Unavailable, Please Login