Big problem with UIRT2 (again)

[shadowsoul]

Wrote about this a few months ago but i didn't understodd what was wrong.

Now i've resoldered my previosuly nonworking UIRT2 (after long discussions with Luc i found the bandit had to be that i didn't get enough power to the UIRT2 to program it, i only got 8.3V on pin 4). I made a PCB for the new one.

The problem is that i now get the same error. (error programming at 0x00000, using Jon Reese's firmare programming with Daniel Ptijcars programmer).
I measured and i still only have around 8V at pin4...

I managed to program the PIC succesfully by using only program instead of program/verify but i can't run Jas39's testprogram, it only gives the Write error (6).

I've checked all the solderings and such and there aren't any briges.
I've also measured the voltage everywhere and the voltage is 13.5V from the pin that connects to R3. On one side of R3 i have 13.5V and on the other side (measured at the legs of the resistor) i have 7.6V or so, meaning it all drops at that point. Should this be the case?

Any help or really anyting you can come up with that may spook is really appreciated as i'm getting kinda tired of this, have spent some 50 hours in total now with it and it still just plainly refuses to work :(

[Luc]

For correct programming you need 12 to 14V on pin 4.
You have a voltage drop so one of the components connected to pin 4 is either bad or wrong installed.
Programming the PIC without verify doesn't mean it's actually programmed. The programmer does what it has to do but the PIC can't due to the pin 4 voltage.
ICSP is something with definitly works, I programmed 50 at least and others ....
Verify the parts with the part layout (Not the picture) but I think you've already done this and must be overlooking something.
Can you mail a picture of your unit to me?

Luc.

[shadowsoul]

Ok, back to checking (yet again) and comparing then *sigh*

Yeah, i think i can manage to get a few decent pics now that i finally got my webcam up and running. Shouldn't be a problem mailing it to you.

Checking towards the layout now than (if i've understood it right layout is "wieved" from above=

[chavex]

Dear sirs,

Please remember that not every PC has the same RS232 voltage levels. The protocol is a bit flexible. For example some laptops don't even go further 5V and do not generate negative voltages.

I would try with a different pc. On the other side i have successeful programmed the pic with only 9V on the MCRL pin with my UIRT2 prototype PCB that you can see in other posts.

[shadowsoul]

Dear sirs,

Please remember that not every PC has the same RS232 voltage levels. The protocol is a bit flexible. For example some laptops don't even go further 5V and do not generate negative voltages.

I would try with a different pc. On the other side i have successeful programmed the pic with only 9V on the MCRL pin with my UIRT2 prototype PCB that you can see in other posts.

As i said i've measured and i do bhave the rigbht voltage until i hit R3. Over R3 there is a decreasement in the voltage of some 5-6V...

Luc: I've checked all the components and such against the layout but as far as i can see it's all correct :/

One thing i'm not so sure about is my Zenerdiode....it's huge (i mean huge, like a cm length or so and 5-7mm diameter). I'm not so sure about if it is indeed the correct values and such on it as i don't know how to check it...
If it has the wrong values would that make the voltage drop?


Oh, and i just remembered: The Input-shunt...what exactly does it do? I Asked my teacker in electronics and he said it was to connect an external thing.
Thx.
//Linus

[Luc]

If the zener is wrong it could well be, what are the markings on it?

The input is indeed to connect an external switch wich will generate an event in Girder, so it can be used just as if you would press a button on the remote.

Luc.

[shadowsoul]

Ok, zener has the following markings:
A ring with something similiar to an M in it (i figure this is the producers mark) followed by a big K.
1N
53
39B
624

(i have no idea of what those marks mean cause we just ordered a bunch of 5.6V zenerdiodes but i don't know if they sent the right ones :D )

[Luc]

So it's a 1N5339B wich is a 5.6 zener diode but at 5W.
I would remove it and check if the level at pin 4 is correct, this should point you in a good direction.
If it doesn't can you mail me a picture?

Luc.

[shadowsoul]

So it's a 1N5339B wich is a 5.6 zener diode but at 5W.
I would remove it and check if the level at pin 4 is correct, this should point you in a good direction.
If it doesn't can you mail me a picture?

Luc.

Hmmm...i'll check that. Just: How to remove it? Solder a cable over it so the power can still bypass it or remove one of the legs completely?

I'll mail you a picture of it as soon as i can take a decent one. E-mail is in your description right?

[Luc]

You should remove one leg or remove it completely, not bridging it with a wire.

Yes, use that email address.

[shadowsoul]

You should remove one leg or remove it completely, not bridging it with a wire.

Yes, use that email address.

Checked it, gets just above 5V witout zener, just below with zener.

Mailed pics to you.

Thx
//linus