If at first you don't succeed!!!!*****?????!!!!

[johnca51]

My first attempt was a failure, but not one to be beaten, I am going to build another and another until I get one working.
I do not know what I did or where I went wrong but my first motor decoder was unsuccesful except for almost setting off the smoke alarms .
I could not believe it when I tried to find what the problem was, I had a short between the black and red track wire where it attaches on the strip board. Of all places the very last thing I soldered on to the board.
I had to laugh!!! unbelievable!!! Just goes to prove I am in the very early stages of electronics and have a long way to go.
One thingI was happy about was that the rest of the effort was better than I expected and when I got out the extra strong magnifying glass ( the eyes are not what they used to be) i could not find anymore un-wanted bridges between the strips. Not only that, my soldering techniques appear to be improving somewhat. (just got to get the eyes on the improve).
Not really knowing specifically how to check if I damaged any of the components I dismantled the board and parts as best I could and then sat down in front of the laptop and sourced information from electronics sites as to how to check most of the components using a multimeter. As it turned out all of those I could test were OK so I probably did not need to dismantle it after all.
I intend starting on another one tomorrow and hopefully this one might be a bit more successful.
If not expect to see me asking a few questions this time around. Ha! Ha!
All things considered I did get pleasure out of having A GO and although it didn't work I may have stumbled on a new circuit for a smoke making circuit! LOL!!
Will let you know how I go with the next one.
Regards
John

[murphyfp]

Hi johnca51
That is what is known as tuning for maximum smoke.

[Paul Harman]

If you have more trouble, it is well worth doing the static testing described in the manual which will quickly identify if any components are damaged.

As long as you check for adjacent shorted tracks before applying power you are unlikely to damage anything.

[johnca51]

Hi all,
Started building a 8 function high output decoder today (after the smoke cleared from the motor decoder disaster). A question I have is- it shows the emitters on the BC182L transistors are connected to a wire running around as 0volts. does this wire attach to the board anywhere or does it just link the emitters. Also, it looks like it may connect to one leg of the regulator, or is just that the line depicting the wire passes over the leg in the diagram?

Back to the motor decoder, just wanted to confirm, on the strip board view showing the placement of the components, as they are mounted vertically, I am a little unsure about diodes D3,D5,D6 and D2 as to which way up they go. Is the end with the band at the top or on the bottom closest to the board. those lying flat indicate which way they lie whereas the vertically placed do not. Looking at the schematic it shows all diodes the same way but I just want to be sure.
Also , if using an electrolytic 1uf 35v capacitor in C1, does the positive side fix to the bottom or +5 volt strip?
Thanks in advance
John C

[chassar90]

Hi johnca51,

First of all the emitters (seems to be a mistake meant to be collector i believe, but wont matter aslong as you connect as per the visuals) only connect to the 0v line. This is the strip i have highlighted in the drawing "0v". DO NOT also connect this to the regulator, as this would short out, causing the regulator to more than likely smoke...

As for the motor decoder, it is almost identical to the function decoder as far as the power circuitry goes. The 4 diodes should all have the same orientation, i.e the ones that lay flat the bands all sit towards the top, the bands on the vertical diodes, should be furthest away from the board.

and last but not least, the positive side of C1 ( if you are following the instructions) should be attached to the strip nearest the edge of the board, and the negative to the 0v rail as mentioned before.

Hope this helps.

Paul

Attachments:

[johnca51]

Thanks Paul,
As it turns out I have those diodes the wrong way around so I am glad I asked the question.
Is that a mistake on the instructions, showing emitters instead of collectors?
You mention the wire linking the collectors is connected to the zero volt strip ( if I read it right) however one of the regulator legs is attached to this strip and I don't want it to smoke.
Sorry about the confusion from my side but my knowledge is somewhat limited on this stuff and I want to get it right.
Kind regards
John C

[chassar90]

hi John, after a bit of searching i have found Differing BC182's, if you search for BC182 in a google image search, it can be seen that looking at the flat side of this transistor, from left to right most say, collector, base, emitter. however as the instructions use a BC182L, which completely changes the pinout. best bet is to get a datasheet for the transistors you are using and wire up as per below:

Base should be connected to the Chip via a transistor.
Emitter should be connected to 0v.
Collector is the function wires for the decoder.

As for the Emitter being connected to the 0v strip, this will be fine, as a regulator has a 0v connection, one side of the regulator is around 20v depending on DCC controller, and the other side nearest the chip is 5v. middle leg is usually 0v (it is if it is a 78L05).

Hope this helps

Paul

[murphyfp]

The way he BC182 is connected is known in electronic terms as a Open Collector Output Stage.

This is the normal configration for control circuits. The Emitter is always connected to Ground oV and the load connected to the Collector.

So in effect the Transitor BC182 is a Off / On Switch in series of the output circuit.
Hope this helps

[johnca51]

Hi again,
Must be doing something wrong!!!!!*****?!!!.
My high output 8 function decoder finished up the same way as my first effort with the motor decoder .UP IN SMOKE!!
As soon as I connected it up to a 12 Volt DC 500mA (max) power supply to test it it beacame very hot and started to smoke. The large resistor, R15 seems to be what is causing the smoking as it is showing dark burn marks on the casing.
I checked all of the diodes to ensure they are the right way around and also checked to see if I had bridged any of thetracks on the strip board.
Everything seems to be OK.
I have just noticed that I was supplied with UF 4007 and not UF 4001 as per the component list.
Could this be the problem or could it be that the power source is the problem?
If anyone can suggest anything else I can try, do, check or change please let me know as I am getting a little frustrated, however determined to get these things working.
Look forward to hearing from you.
Regards
John

[Paul Harman]

It sounds like there is a short somewhere. The diodes sound like they are OK (and 1N4007 will be fine). You should not be able to fry them with your 0.5A power supply.

First check is to connect a meter across D3 and measure the voltage there. If it 0.6V or thereabouts you could have D3 the wrong way round, if lower it could be a problem with the regulator or C1 the wrong way round or a short between the two adjacent tracks on the stripboard. Getting D1 the wrong way round will fry the regulator (D1 stripe end should be connected to R15).

Any fault further down the line should not result in smoking R15 if it is a 2W version, but a 0.5W R15 will probably get very hot if there is a short on the output of the regulator.

There is no need to panic, simple elimination of possible problems will resolve the issue.

[johnca51]

Hi Paul,
I found the problem. It appears that on both attempts so far I had D3 around the wrong way. Obviously my lack of knowledge caught me out. To determine which way the diodes went I looked at the circuit diagram and took it as the diodes were all the same way. When I looked at it more in depth it became obvious that the D3 was the opposite way around to all the others.
Once I changed it there was no smoking and when I did the voltage checks on the IC socket all pins were the voltage as suggested.
I will connect it up tomorrow to a loco and see how we go.
Thanks to all so far for the assistance so far and I will let you know if I have indeed had success this time.
Regards
John

[johnca51]

Hi All,
I had to put my progress with the decoders on hold due to being un-well for a while.
I have now built up a total of 8 motor decoders and when I started to install them I encountered problems. Not with the installation but with getting them to function.
I downloaded the hex files onto the PIC and the dats was verified. I tried a total of 12 PIC's but no go.
I have gone over time and time again, all the information supplied regarding the placement of components on the board and I have got 99.9% of the components to the values suggested. I have double checked there are no shorts across the tracks on the board.
The voltages on the PIC pins are as follows
Pin 1 and pin 8 = 4.9 volts
Pin 2 0.00v
Pin 3 0.00v
Pin 4 0.00v
Pin 5 0.00v
Pin 6 2.5v
Pin 7 0.4v
I have 6 volts on the top of the vertical components as suggested.
These voltages are taken with the black multimeter lead on pin 8 and using the red lead to touch the other pins.

These voltages are measured using a DC powerpack putting out 11.5 volts at 500mA. as the power source.
I have also tried it on a Bachmann DC train controller with similar results.

I have a 12 volt motor attached to the decoder which when I apply power to it operates freely.
Are they like factory decoders, whereby once installed they should operate straight away on address 3 or is there some additional programming to be done?

Can anyone throw any light on what I need to do or can do to get these operable as I really have spent a whole lot of time chasing parts, assembling them and trying to work out why i cannot get them working, which is starting to get a bit frustrating.
I guess this is all part of the learning curve!!!!


Hope someone can help.
Kind regards
John C

[johnca51]

Hi again,
Thought I should make mention the decoders I have assembled are the Motor Decoders only
John C

[kennedylanduk]

When you say the motors operate freely, is this on an analogue track?

I'm sure mine spin at full speed on the analogue track. But once connected to the digital controlled track they work fine.

I also went through a lot of learning to get mine to work.

[johnca51]

When i say the motors work freely I mean when I check them on a DC source so it is not the motors at fault.
It is really starting to frustrate me as I have done every thing i know of with my limited knowledge to get these things to work.
John

[johnca51]

i connected the decoder to my Digitrax controller today and found the L272 IC got extremely hot, so much so that when i touched it I was left with a blister on my finger. Is this normal??
I am becoming more frustrated but am not giving up.
Please help me !!!
John

[kennedylanduk]

Yes, the heat is normal.

Have a look at
diydecoder.proboards.com/index.cgi?action=display&board=motor&thread=14&page=1

It sounds like you are in exactly the same situation that I was. There is a software mod that can bring the heat of the chip down quite a bit.

Tony.

[johnca51]

I never thought that i could get so frustrated with a project as I am getting with this one. I am starting to beleive that the two PIC programmers I have purchased off of eBay may not be programming my PIC's correctly. One is a clone of a PICKIT2 which as yet I have not been able to even get working and the other I think may be dodgy.
Yesterday I ordered an original unit from Microchip, end of another $60.00US so I can be sure that the PIC's are programmed properly. By the time I have finished with this whole excercise it probably would have been cheaper to by brand name decoders. However, like i have said from the start, I will not be beaten and will succeed because i beleive that once i have it all worked out I have plenty of uses for these now and down track.

John

[kennedylanduk]

I got really frustrated as well John. But I did get everything working in the end.

My programmer is a PICKIT2 clone and programs the chips fine. But it's over a year since I used it so cannot remember at all what I did/didn't do to make it all work.

[johnca51]

The programmer, a Pickit 2 clone, that I currently have which is a new one from eBay will not work on my laptop because apparently it is not compatible with Windows 7. What operating system did yours work on, can you recall?
John

[kennedylanduk]

I'm not sure. I went to Windows 7 around this time last year so it was probably XP (32 bit).

[Paul Harman]

Hi John C, sorry to hear that you are having trouble.

Just a couple of points to note.

1. There should be around 0.6V (two thirds of one volt) and not 6V (six volts) on the top of the vertical components measered with respect to pin 8 of the PIC. If this voltage is 6V it will indicate that the vertical diode has been inserted upside down. The stripe end (cathode) should be at the bottom.

2. The motor decoder will not respond to 126-step packets, so you will need to ensure that your command station is sending 28-step, 27-step or 14-step packets.

3. Adjusting CV9 to tune the decoder to your motor should result in the L272 running cooler. The default setting is for the quietest mode but that does not suit all motors.

[johnca51]

Hi All,
Merry Christmas!
I hope you all had a good one, Mine seems to have been consumed with these damned decoders.
I do not know what I am doing wrong but the frustration levels are fast approaching the stage where I bin the lot.
I have now bought a total of three Pic programmers, the first two I thought were dodgy or not working, the last cost me $60.00US from microchip so one would think that it would work.
I have re-programmed all of the Pic's I had and have also bought some new ones so as to start completely from scratch.
When I program the pic's it says programming successful, but when I try to verify the data I get this message;-
"Verification of program memory failed at address 0x000000"
I have attached a copy of what is showing in the data after I program the Pic.
I finally got all the voltages right on the board itself and tried to program the CV's into the decoder nd each time I made an entry for each CV my DT400 digitrax controller beeped and indicated the CV had been accepted by showing good on the screen.
I have now assembled six motor decoders and cannot get a single one to work. Needless to say I am almost at the end of my tether with these things but having spent so much time and money on them I cannot now afford to give up. My wife is now saying to me " give it away if they are getting too much" so it, or my attitude is starting to show.

Can someone please throw any light on where I am failing.
kind regards
John C

[johnca51]

Hi
Here is the attachment with the data on the PIc's
John c

Attachments:

[kennedylanduk]

Have you made sure that the controller is outputting 28-step speed data? It took me a while to get mine to do this (a Hornby select controller)?

[johnca51]

I tried this. My Digitrax controller shows 14 steps on the screen when I select the decoder on Loco 3 so I am sure I have got that right.

I think my next step is to build another decoder from scratch.

I bought a new roll of solder today to go with the $500.00 soldering station my Daughter, Son-in- law and grandkids got me for Christmas.
I have also got some new PIC's which I will programme with my new Microchip Pickit2 programmer.
I have also cut up some new stripboards.

If this one does not work, I will seriously have to think about giving up and devoting my time to things that will reward me for my efforts.
John

[kennedylanduk]

I'm just sorry I cannot be of more help at the moment. I went through heartache to get mine working, but am just too busy to dig everything out at the moment. I'm not even sure where my programmer is at the moment.

[johnca51]

Hi Tony,
Mate,
i appreciate the help and encouragement you have given me so far. It must be something simple or something I have missed.
Although I sound despondent I am really not one who gives up easily and I will continue to persevere with it until I get them working.
John

[johnca51]

I built up another decoder today and took my time ensuring everything was 100%. The voltages were all good and there were no shoted tracks. I connected it to my Digitrax LT1 decoder tester and set my DT 400 controller at both 14 and 28 steps but still I have no joy in getting it to function.
All I can think of now is there must be someting wrong with the programming of the PIC.
Can someone tell me if the data that is loaded on the PIC, with the programmer, contains the CV's necesrry to run the decoder on LOCO 3 straight away or is there additional CV programming that needs to be completed before it will run.
I really know very little about Hex files etc. however with my Microchip programmer I was able to get it to say that the data was loaded successfully but I could not get it to verify.
Look forward to hearing from anyone who can throw any light on the situation.
Regards
John

[Paul Harman]

The program memory should verify OK, but the EEROM data memory will not because as soon as the PIC is programmed it will populate the data EEROM with the default CV settings. Once CV7 and CV8 are set correctly the CV settings will not be changed at power on, but will never match the state they are in when initially programmed.

Some programmers have the option to switch the power off to the PIC while it is in the programmer which should stop the data EEROM memory being changed before it is verified.

Presumably you are using a 12F629, other PICs will possibly not work.

It is worth making sure that you are verifying the program memory only.