Using my DVA on my digital Fluke

[cityjack]

Hello all,

I am presently working through troubleshooting my rectifier/regulator on my 93 175 Fast Strike with another gentleman here on this forum. He's been a great help in providing me an accelerrated and easier way for me to test my charging and tach system. I have the OEM service manual but it is complicated as heck to use for these particular tests. I went and bought the DVA for my digital Fluke. I was under the impression that my digital Fluke always needed to be on DC for these DVA as the DVA allowed me to record a dc voltage from the AC peak signal. Am I wrong? Will there ever be a time when you use the AC setting on the meter with the DVA hooked up?

Thanks

Sid

 

[clanton]

Re: Using my DVA on my digital Fluke

No, not according to the instructions that came with my adapter. Can`t use auto range. You can use the meter without the adapter set on AC scale, X the results by 1.414 will give close to the same number. I have a Fluke 88 with 2/3 adapters, plus the real peak reading meter. I like the real meter, but they all work.

 

[cityjack]

Re: Using my DVA on my digital Fluke

Thank you sir,

I am trying to troubleshoot my 1993 175hp Fast Strike. The motor starts and runs fine. The tach stopped working so this is what has caused me to start down this troubleshooting path of the rectifier/regulator. A nice person here started to help me but I got lost in his instructions on troubleshooting. I purchased the DVA for my digital Fluke. These are the test I have started and completed so far. Any help or clarification would be greatly appreciated.

1. I was told to check the NON DVA (my meter on DC)voltage at the battery while running(at idle, rpms not sure since no tach)and compare it to the voltage at the purple wire coming out of my regulator. They should be the same. They were 12.30 and 12.31 respectively.

2. All wires connected and engine running at 1500 (mine is at idle), check DVA voltage(my meter on DC) from each yellow wire individually from the regulator to gnd. Should be within 2 volts of each other. I got 10.99 and 11.01 If readings are equal, go to step 3, if not, go to step 4. I do not know if 11.01 and 10.99 was too low, but they were equal or within 2 volts of each other so I went onto step 3.

3. Check the DVA voltage (my meter on DC) from yellow wires individually to the red wire going to the solenoid(checked at solenoid lug). The readings I'm told again should be within 2 volts of each other. I got zero on both yellow wires. I double checked. NOTHING on either wire.

I stopped here

4. If readings from step 2 were unequal, mark across the connection between the stator and the regulator/rectifier on the low side. Turn engine off and swap stator leads. Start engine and retest. The component that has the marked wire with the low reading is bad.

I totally do not understand what step 4 is telling me to do or if my problem has been found before I even got to step 4.

Please help. The OEM service manual is crazy with all its variable load tester and inline ammeter and cd adapter box. there has got to be an easier way. Can I do the resistance checks on the stator? Will that give me a strong confidence that it is feeding a good ac signal to the regulator/rectifier? Like I said, the motor starts and runs fine. Just no tach and I am not sure if its even charging the battery. I am assuming it is NOT charging by only getting 12.3 volts at the battery while running at idle. I guess maybe I need to make sure I am at 1500rpm to make SURE its only 12.3 to the battery and the purple wire while running.

Help please.

Thanks

Sid

 

[Faztbullet]

Re: Using my DVA on my digital Fluke

Its within specs(2 volts) if they was not you go to step 4. You are correct to got to step 3 and test and you should see a 4-8 volt reading.

 

[cityjack]

Re: Using my DVA on my digital Fluke

Hey Mr. Bullit,

Are you saying that the DVA voltage of 11.01 and 10.99 is good from the stator to the regulator? But you said I needed to have my meter on AC for step 3. Is that ac on the meter AND with the DVA? I thought the DVA was only for dc measurements only. Is my stator ok? Does the purple wire supply 12v to the regulator to make it wok? What is the black wire coming out of the regulator for?

 

[clanton]

Re: Using my DVA on my digital Fluke

Are you reading these steps from a manual?

 

[cityjack]

Re: Using my DVA on my digital Fluke

No sir. The OEM service manual is complicated to say the least with all of its variable load tester and inline ammeter and cd adapter box. There has got to be an easier way. Mr. Fastbullit was suggesting these steps. I just wanted to find out why my tach was not working. I bought the DVA adapter to help me along the way with my digital Fluke. Mr. Bullitt suggested these steps as an easier way and I got confused by his directions. As you can see above, I followed his steps with my readings stated above but got stuck after step 3 when I got nothing. Mr. Bullitt told me to put the meter on AC and that I should be getting something in the reading of the red to yellow wires. I was using the DVA and on the DC setting and got nothing. So I stopped there. I figured the readings that I got in step 2 were not right either. I was not sure. I am thinking that on the yellow wires to gnd I should have gotten more than 10.99 and 11.01. I was not sure so I just moved onto step 3 where I got nothing. I was really hoping this DVA would have been easier. Unfortunately, there are no directions with the DVA except for some complicated list for Mercs.

Just need help sir.

Thanks

Sid

 

[clanton]

Re: Using my DVA on my digital Fluke

The easy way to check the tach signal wire is to locate the gray wire at the tach, Connect the red lead to the gray wire, black wire to harness ground. using the DVA adapter you should see 9 +- 1 volts at 1000 rpms. If this test is good, tach is bad.

If less then 8 volts, disconnect tach, retest. If voltage moves up to correct voltage, tach is bad.

You will have to have a breakout box , a set of meter leads with the piercing tips to pierce the or cut the wire.
I use the meter leads with the piercing tips.

 

[cityjack]

Re: Using my DVA on my digital Fluke

The easy way to check the tach signal wire is to locate the gray wire at the tach, Connect the red lead to the gray wire, black wire to harness ground. using the DVA adapter you should see 9 +- 1 volts at 1000 rpms. If this test is good, tach is bad.

If less then 8 volts, disconnect tach, retest. If voltage moves up to correct voltage, tach is bad.

You will have to have a breakout box , a set of meter leads with the piercing tips to pierce the or cut the wire.
I use the meter leads with the piercing tips.

I have the leads with the piercing tips. What is a breakout box? Another question please. When taking measurements at the regulator rectifier the other night, right on top of the regulator/rectifier closest to the center of the engine there was some brown, what looked like hardened syrup that has dripped or oozed from somewhere and come to rest on my regulator. Any idea what that might be from?

Thanks

Sid

 

[Faztbullet]

Re: Using my DVA on my digital Fluke

Diode usually blown in rectifier causes the melted bubble on surface. Do the bench test and if it fails( which I think it will) replace rectifier. The purple wire turns the rectifier on/off and replacements do not have this wire.

 

[cityjack]

Re: Using my DVA on my digital Fluke

Diode usually blown in rectifier causes the melted bubble on surface. Do the bench test and if it fails( which I think it will) replace rectifier. The purple wire turns the rectifier on/off and replacements do not have this wire.

Thanks a ton mr. Bullet. I see you know what I'm talking about with that brown melted stuff that looks like syrup on the regulator. I was just hoping it didn't come out from the stator. I will remove the regulator this weekend and benchtest. I will report back. Thanks for the early reply too and have a nice weekend sir.

Sid