MK4 Attempted Repair - Page 2

roadnutter · 11th March 2015, 10:52

fixed that...c2 smd smoothing cap up near the main connector on the bottom had shorted to ground...that could have been expensive...I'll post you those pics of the board shortly

Avora · 11th March 2015, 11:03

Quote:

Originally Posted by roadnutter

Yes I was thinking about it last night and thought it may befor the GPS send and return for the other chip. I'm lucky that I've got a known good system here, its just getting the time to test!

Or at least I had a working system...just accidently shorted the centre pin on the power switch BTS442E2 to pin 2 by slipping with the multimeter and now its totally dead...pin 2 was ground at the time. Hoping its the overload protection but not sure.

I actually did this as the 12V input is the small tab. I presumed it was ground. Woops. Luckily there was no magic smoke, and still works. I think that part is available but for around £10.

I will hopefully get to test the drive again today, depending on the weather. I may need to test it with the lid off to see what the ibus is doing if it doesn't work.

Avora · 11th March 2015, 16:09

Ok, I got a chance to have a play in the car. First time installed and it attempted to boot up with a fancy Rover logo and the radio on in the background. But still got no further, no response.

And I have found that the iBUS doesn't turn the nav on and off. With a Power LED I can now see, it is pin 3 on the purple connector (be sure to read the tiny numbers). Give this 12V, as I had to whilst testing, and the drive will start up, take it away and the LED starts flashing and after a minute or so powers the drive off.

So I brought the drive back inside for some more poking around, the ST202EB chip appears to be working just fine. I really need to test the drive in the car whilst it is disassembled, or get a test bench going to fully trace the iBUS. It is still my main target. It is still good to see it doing something. And the Rover logo looks good.

roadnutter · 11th March 2015, 16:41

Pin 3 on the purple connector is the ignition feed. It will bring the unit to life if 12V is applied.

If you have 12V on pin 3 and hold eject do you get further?

I have found that pressing eject basically gives 12V to the LE50 chip that is at the front bottom of the board near the power light. This LE50 then outputs 5V that goes to the DAC http://www.alldatasheet.com/datashee...T1181AISW.html chip that is near the big 2200KOhm 16V cap on the other side of the board.

On my problem board, as soon as I remove the 12V, rather than it holding power for a while then flashing and going off, it just dies. Any idea what is doing the latch / delay for the power?

Oh my boards are both slightly different on the bottom from yours near the LE50 chip and burned area. The chip near the LE50 is a RS232 serial chip LT1180A/LT1181A but not sure what it is doing.

James

Avora · 11th March 2015, 16:58

If you notice there are two transceiver chips together, mine are ELMOS near the shielding can, there is also another RS232 chip, the one on the bottom is there solely due to space restrictions I expect. Everything runs back through the board to the top side. So everything appears to be doubled up, I haven't yet traced the second set yet. I will get around to it soon.

The bus comes in at 12V, gets reduced down to a sane level, appears to go through a hex buffer chip then up to the RS232 chip. From here I presume, but haven't checked, it goes in to the shielded area through another chip and hopefully ends up in the main chip for instructions.

Pressing eject does nothing extra for me, just ejects the disc, I already have a solid 12V input. It sounds as though you aren't getting the battery 12V through to the correct place and it is having to go through the button

I only followed the input voltage section for a brief time, I soon discovered that pin 3 enabled the drive.

roadnutter · 11th March 2015, 18:31

Hi agreed...I'm now spending a bit of time when I can to check where one board has 12V and the other doesn't without blowing any more caps!

If you need any traces from my good board let me know.

11th March 2015, 16:09	#13
Avora Loves to post MG ZT-T 190 Join Date: Jul 2014 Location: Penrith Posts: 441 Thanks: 89 Thanked 69 Times in 56 Posts	Ok, I got a chance to have a play in the car. First time installed and it attempted to boot up with a fancy Rover logo and the radio on in the background. But still got no further, no response. And I have found that the iBUS doesn't turn the nav on and off. With a Power LED I can now see, it is pin 3 on the purple connector (be sure to read the tiny numbers). Give this 12V, as I had to whilst testing, and the drive will start up, take it away and the LED starts flashing and after a minute or so powers the drive off. So I brought the drive back inside for some more poking around, the ST202EB chip appears to be working just fine. I really need to test the drive in the car whilst it is disassembled, or get a test bench going to fully trace the iBUS. It is still my main target. It is still good to see it doing something. And the Rover logo looks good. __________________ ZT-T 190

11th March 2015, 16:58	#15
Avora Loves to post MG ZT-T 190 Join Date: Jul 2014 Location: Penrith Posts: 441 Thanks: 89 Thanked 69 Times in 56 Posts	If you notice there are two transceiver chips together, mine are ELMOS near the shielding can, there is also another RS232 chip, the one on the bottom is there solely due to space restrictions I expect. Everything runs back through the board to the top side. So everything appears to be doubled up, I haven't yet traced the second set yet. I will get around to it soon. The bus comes in at 12V, gets reduced down to a sane level, appears to go through a hex buffer chip then up to the RS232 chip. From here I presume, but haven't checked, it goes in to the shielded area through another chip and hopefully ends up in the main chip for instructions. Pressing eject does nothing extra for me, just ejects the disc, I already have a solid 12V input. It sounds as though you aren't getting the battery 12V through to the correct place and it is having to go through the button I only followed the input voltage section for a brief time, I soon discovered that pin 3 enabled the drive. __________________ ZT-T 190

11th March 2015, 10:52	#11
roadnutter Newbie None Join Date: Mar 2015 Location: Glasgow Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts	fixed that...c2 smd smoothing cap up near the main connector on the bottom had shorted to ground...that could have been expensive...I'll post you those pics of the board shortly

11th March 2015, 16:41	#14
roadnutter Newbie None Join Date: Mar 2015 Location: Glasgow Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts	Pin 3 on the purple connector is the ignition feed. It will bring the unit to life if 12V is applied. If you have 12V on pin 3 and hold eject do you get further? I have found that pressing eject basically gives 12V to the LE50 chip that is at the front bottom of the board near the power light. This LE50 then outputs 5V that goes to the DAC http://www.alldatasheet.com/datashee...T1181AISW.html chip that is near the big 2200KOhm 16V cap on the other side of the board. On my problem board, as soon as I remove the 12V, rather than it holding power for a while then flashing and going off, it just dies. Any idea what is doing the latch / delay for the power? Oh my boards are both slightly different on the bottom from yours near the LE50 chip and burned area. The chip near the LE50 is a RS232 serial chip LT1180A/LT1181A but not sure what it is doing. James

11th March 2015, 18:31	#16
roadnutter Newbie None Join Date: Mar 2015 Location: Glasgow Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts	Hi agreed...I'm now spending a bit of time when I can to check where one board has 12V and the other doesn't without blowing any more caps! If you need any traces from my good board let me know.