The stripe would indicate the position of pin 1 if it is on the left looking at the ic with the part number the correct way up.

Will check the diode readings.

Timescope

 

Ok, thats what I figured but wanted to be sure.

 

I would get .47mV with the leads this way and 000 when switched around

.47mV or 470mV ? 000 or "OL" ?

Does that mean all these diodes are bad?

No they are ok. The reversed readings are caused by the various circuits that are connected to the outputs of the supply, the loads.

Timescope

 

Sorry yea its 470mv and "OL" when switched the opposite way

 

R3 is to be a 560Ω, Im getting .560kΩ

These readings are correct: 1kΩ = 1000Ω

Timescope

 

Ok, just weird both my mulitmeters wouldn't read anything on Ω, I had to switch it to kΩ to get a reading

 

So everything else looks good? And replacing U3 should be the problem?

 

The only component we did not test is the TL431C. Do you have a 4.7kΩ resistor on your scrap board ?

1. Connect the 4.7kΩ resistor to the +ve terminal of your 9v battery

2. Connect the -ve terminal of the 9v battery to GND which is connected to pins 2, 3, 6, 7 of U7 (TL431).

3. Connect the negative probe of the diode test meter to the above GND

4. Connect the positive probe of the diode test meter to TP21 (TL431 pin 1)

5. Connect the other end of the 4.7kΩ resistor to pin 8 of TL431 (connected to R20, R19 etc)

6. The reading on the diode test meter should change when the 4.7kΩ resistor is connected to pin 8.

Timescope

 

Hey good news....Put U3 on and put board back in to see if anything changed and it worked! I was stunned! Ran it threw a few cycles and tried out the braking circuit and everything seems normal.

One thing that I had wondered before all this happened is when its plugged in but not running there is like a constant very quiet hiss coming from the board area. You have to put your ear fairly close to hear it but its defiantly there. It did this for sure before like I said, and I just remembered when I herd it again. Any Idea what could cause this audible tone? I dont believe its from this board we were working on but maybe from the large blue DC capacitors that sit under this board, or the second PCB? Its probably normal, just curious what it is. Almost sound like a slow air leak.

Timescope I cant thank you enough for all the help you have given me. I greatly appreciate it! If you have a paypal acc I would like to send you a thank you for all your time.

 

Congratulations for a job well done. You showed patience and dedication and it was my pleasure to assist you.

The noise is generated by the high frequency switching of currents in the magnetics and is not a problem.

Timescope

 

One last thing if you dont mind. Here is what I was trying to find the 9 volts for in the beginning. http://www.machtach.com/About.html

Bottom of the page it says 7-9v at 200ma

So can I still pull that 8 v off key 8+? If so where would be a good spot to do so for the+ and the - connections?

 

The +8_KEY voltage is available across C19, negative to GND, positive to +8_KEY.

This supply is rated at 725mA. I will take a look at the link at machtach to make sure it will not overload the supply.

Give me a few minutes.

Timescope

 

I have looked at the MachTach user manual .

200mA looks a lot to add to a supply rated at 725mA when the current the existing Baldor circuit requires is unknown.

What of using another separate supply for the MachTach ?

Timescope

 

Ya I can do that, I was just trying to simplify things but ended up causing all this. At least I leaned allot about circuits. LOL. Thanks for checking into it. Glad I asked before wiring it up and causing more issues.

 

Good. Prevention is better than cure.

Timescope

 

Did you have a paypal acc that I could send a little thanks too?

 

I wish I had then it would be easy for me to order spare parts.

Here in Sierra Leone we do not use credit cards etc. I tried to get a visa card from the bank sometime ago and am still waiting to hear from them.

Don't worry, I have been adequately rewarded with your kind thoughts.

Timescope

 

You can use a paypal account with a checking account. They verify it and think you use the routing number. Credit cars are nice sometimes but can get you in trouble fast. If you have a checking account you may want to look into it. I use paypal more then anything now a days. Its cheaper to buy whatever I need and usually most places have free or reasonable shipping and its still way way cheaper then getting local. Plus specialty items are not carried local and more and more stores are going out of business or stop carrying these type of items because they cant compete with online stuff. It sux but its how it is.

I really would like to send you something for all you help, you don't know how lost I was, as long as I had someone with brains say check this or replace that I could do it. But to try and figure out whats what off a schematic was way beyond me. Allot of math and knowledge involved. Do you have western union near you? I could send you money that way.

 

Hi Timescope, Had a question about encoders if you know about these at all. There is this saw at my work that has a simple computer that you can tell it to cut a certain size and it uses this encoder (below) to cut the precise dimension. What I am looking to do is tap into the signal coming out of the encoder and wire it into a separate display to read out in "inches" and have the ability to zero when ever desired. Do you have any idea where to start? Im sure there are a vast amount of products that would work, I just need something super simple that I can setup to readout in 1/16, 1/8, 1/4 and so on. I know this isn't the place to get help on that, but you are very knowledgeable so I thought Id see what you thought.

 

Hi diebog, sorry for not replying earlier but my modem has problems and I am using my phone.

I'll send you a PM when I get the line up again.

I have worked with encoders, stepper motors etc and I would suggest that you start a new thread about that topic so that the pic and avr guys can chip in with a simple solution.

Have to go before my phone does.

Timescope