This information can be useful if you have a faulty connection to the U815. These are mainly the Clk/Rst and I/O connections. Good luck with it. On request a newer version of it with a better connection overview of all the six connections. At least the ones I could find out. Click on the picture to see it fully.
Johnny, do you know what kind of IC U815 is? Is there any datasheet available? I have DM8000 and there is no voltage coming to SIM card( neither CLK, RESET ...). I measured and there is neither Vin voltage coming to U815. Do you know where input voltage is coming to U815 from? Thank you.
The dm8000hd has nearly the same simcard circuit as the Dm800hd. As so this IC U815 which is the same as the dm800hd has, the U16 - sn74cbts3384 Pin 24 is the VCC Supply voltage and may not exceed the 5.5v
Johnny, thanks again for your info about SIM schematic( yes,it is really more or less the same with DM800). I still have one DM8000 with output like this (c) 2007,2008 Dream Multimedia GmbH. All rights reserved. Dreambox DM8000 FIRST STAGE 1.00 {BO2345 It seems to me that output is as if there was no SIM. Yet, there is SIM that was even tested in another box.(=SIM is OK) Is SIM card circuit related to another circuit ? With this DM8000 there is neither OLED working . I was even told that there is U807 (ATMEL) faulty and that chip should probably control that OLED. Have you heard about something like that? Thank you for reply .
The Atmega chip U807 is a programmed chip which has data from the fabric. I do not know much about it, I had only one case which had a death Atmega chip but this was as far as I remember a complete death box. I think, be sure that it's not a issue with the display itself, see also if you measure the frontpanel voltages. Sim card.. Be sure that the sim card pin 1 voltage circuit has no issues as the T810/T809 switch transistors. But, since you say that is also has other issues, it may also be related to the startup. In any case it's not easy to say were to look, but I would thinking of a crystal, most logic and maybe the J100 54.000.
Johnny, Thank you for your reply. I exchanged J100 and T810/T809 but the problem persists Next I put CPU into RESET state( via U1101) and measured Vcc 5V RST 3.5V Clk 5V IO 5V RST seems a little lower .Do you think it can be a problem?
At this moment I do not have a running dm8000hd motherboard but based on my notes without a sim card with of course normally Error on display, Vcc: 1.3v / 5v / 0v Rst: 2.2v / 5v / 0v Clk: 2.2v / 2.1v / 0v i/O: 2.5v / 5v / 0v And with working (japhar) sim card, Vcc: 5v Rst: 5v Clk: 2.2v i/O: 5v
Thanks Jonny this is a great help! What can I say thank you and I wish you a Happy Easter to you and your family! I'll let you know how this surgery is going to end! Enzo from zurich