SUN engine tester. CO HC meter troubles

[MBfreak]

Hi to all!
I am the happy owner of a SUN MCM 2110 engine tester.
SUN Microcomputer motor tester 2110, Model MCM 2110, Serial no R313-22.
It is a very versatile tester for older cars. Unfortunately the CO/HC subassembly that sits inside the cabinet is faulty. The IR light source is low and what is worse is that the two Lead Selen photodetectors for HC and CO are so noisy that the start up routine in the tester displays " CO/HC service required " and displays no values. I am well versed in electronics and have a design outline from the patent , so pinpointing the fault is easy.
What is not easy is to find parts. I have failed miserably, been in contact with 5 european SUN/SnapOn service centers, same story. Too old , not available.
If anybody has any info at all where to source parts , I will be very thankful.
Photos enclosed on the tester and the faulty parts
Best regards from snowcovered Sweden!


Ola

 

[global72]

I have 6 individual detectors. I can almost guarantee that these are the last six new in existence. 15 Years ago I owned a company called Recon Auto equipment. We refurbished off lease equipment and resold it. When Sun announced they were no longer going to produce parts for the 2 gas analyzers we purchased all remaining detectors and some other items.

 

[MBfreak]

Hi there.
Great news. Thanks a bundle!
I am very much interested in purchasing. What I need is the double detector as shown in the picture that has two photo-detectors with the appropriate optical filters. Is that what you have? If you have the individual Lead Selene detector chips ( about 5x3mm with leads that will of course also be OK. I will just replace the existing ones in the assy shown in my middle picture. Would you happen to have the IR-"lamp" also? A used one will be OK.Please email me on [email protected] so that we can close the deal!
And thanks a million.
I have a friend close to Nashville, he can take care of the sending of parts to Sweden to save you some hassle.

Ola

 

[oldgoaly]

Many moons ago I bought 2 1115's, my cousin had a 1015 with the external co/hc which at the time he had calibrated monthly or quarterly. One of my 1115 would not calibrate, so having 2 I did the side by side test, after opening up both, I found the non functioning one to be dirty, so I cleaned it carefully and it performed as new. Sold it, still have the one love it! so if your lenses or mirriors have any dust/dirt/moisture it won't work properly. Good luck! tt

 

[global72]

Before putting the new detectors in the machine it sounds like there is a problem the detectors won’t fix. When the detectors go bad the needles bounce.

If the needles are just laying down and do not jump across the scale when you try to calibrate the machine you have a much more serious problem.

 

[MBfreak]

Hi, and thanks for the advise.

The" needles " ( ie the output voltages that go into te CO and HC channels in the MCM 2110 ), do bounce quite a lot and looking at the output of the first op amps after the detectors there is a very spiky signal, the source of which is the noisy sensor.
I have simulated an input signal from the detectors thru a programmable signal generator we have at work and the rest of the system, ie total amplifier, photo chopper, level locker and comparator is 100 % steady.
So I am very much shure that the source of the malfunctions are the two photo detector assemblies, that sits mounted together on the bracket and connects with a 5pole plug into the electronics.
And I would very much appreciate if you could sell me one cpl CO sensor ( opical filter, plead-selene sensor and plastic mounting bracke and one similar but for the HC measurement.
And if you would have a new or used IR light source , I would be very much interested also in that.

Best regards

Ola Kristofersson
0046 730 928111

 

[global72]

I just have the chips. But the assembly is not that hard to break down.

PM me the address and I will mail out 2 of the detectors.

Merry Christmas

 

[creativeinnovation]

I just have the chips. But the assembly is not that hard to break down.

PM me the address and I will mail out 2 of the detectors.

Merry Christmas

Hi there, I just found this thread on Google, and I just purchased 2 EPA75 analyzers, with the pics on this thread, the IR detectors look the same, one of analyzer's work, and the other has a faulty CO detector, apparently one of the thin wires on the detector is busted off just under the IR filter. I would like to buy 2 pairs of dectectors if you still have them, let me know, also, if you may help me with calibration, where on the unit do I adjust the HC/CO meters when calibration gas is used? for the circuit board and the HI/LOW buttons have trim pots...any help would be SWEET!!!
thanks! and happy new year!!!
Joe

 

[MBfreak]

Santa Claus is alive and well . His real name is global 72 on this forum.
THANKS A MILLION, the detectors arrived in the mail today. I hooked one of them up and the unit now works on that channel, the output from the first opamp is free from noise and the meter is steady on both zero and on full scale in the "mechanical flag" calibration mode.

Again, very many thanks to global 72 who made the repair possible.
I have now gotten hold of the complete schematicg for the CO or HC board for this CO/HC tester.
If anybody needs a copy, please PM me with email adress an I will send straight away.


Happy as a clam

Ola

 

[TOM41KS]

I have a sun 1115 But the ehahust gas anilazer dosen't work. the hoses were in a pile in the bottom as expected.I have re-plumbed it and cleaned all I could find to clean. It won't zero.when 0 is pushed low flow light comes on.I also can't find a manuel Can any body help me.

 

[global72]

Check vacuum at the filter assembly

If you pull the pump heads off the reed valves most likely need to be cleaned or replaced. Also the pump diaphragms are probably dry rotted. Checking those two things would be a good place to start.

 

[TOM41KS]

Thank You for your reply I will pull them apart in the morning.I can't think of any reason they would be good. The 64 dollar question is where do I get new ones.

 

[global72]

The reed valves can most likely be cleaned. There are 2 valves on each side of the pump so a total of 4.

The pump is pretty standard and same or similar are in production still. So the pump diaphragm should not be too hard to find.

 

[TOM41KS]

I checked out the pump, it's OK. I went back and looked at my first post. I gave you incorrect information. The low flow light is not on in zero. When I push span it comes on.

 

[creativeinnovation]

I checked out the pump, it's OK. I went back and looked at my first post. I gave you incorrect information. The low flow light is not on in zero. When I push span it comes on.

Hi there, I have 2 of the EPA75 and mine have both the zero and span button, I noticed that the low flow light only comes on when the span button is pressed, the zero button on mine switches the solenoid on so only ambient air is being pumped into the sample tube on the gas bench, this will allow you to zero the gauges...what exactly is wrong with the unit?
Joe

 

[mokomon]

please send me a schematic of the Co HC testor that you have.

 

[Kuchar]

Here's hoping this old forum is still alive. I just bought a Sun 1115 and I'm having Similar issues with my gas analyzer. My CO bounces and my HC meter doesn't seem to do anything. I've re- plumed all the brittle hoses and cleaned the IR glass and mirrors. The pump works but that's about all I've done. I'm searching for calibration gas and any documentation I can find. I'll try the other suggestions mentioned and see where that gets me. If anyone has a schematic please let me know, and any other suggestions anyone can offer are greatly appreciated. Thanks in advance for any and all help.
Email: [email protected]

 

[DanHoug]

just bought a Sun EPA 75 and looking for the schematic for the HC/CO tester. lots to rehab on this one... all hoses cracked off, mirrors dirty, doesn't power up at all.

-dan

 

[Paul325321]

Dan, I bought one too - Sun EPA 75. Cant manage to calibrate as the needle on the CO gage is bouncing around. Dod you have any luck getting help ?

 

[Paul325321]

I just have the chips. But the assembly is not that hard to break down.

PM me the address and I will mail out 2 of the detectors.

Merry Christmas

I‘m new on the forum, live in Germany (Irish national) and just bought a Sun EPA 75. I have been looking for help, the unit looks great, pump seems to work but I cant calibrate. The CO gauge is bouncing around. I don’t have instructions or service manual but have been reading up on internet. I wonder if you are still participating in the forum and would be willing to discuss my issues ? Thanks, Paul