Those voltages would appear to be correct. With the M100 off it would be residual charge in the cap or leakages somewhere else on the board giving the 0.83V.
Well it was worth checking. It looks like the +5V is getting across and is very healthy. Need to ponder some more on why your DVI is not working. From: M100 <[email protected]<mailto:[email protected]>> on behalf of Brian White <[email protected]<mailto:[email protected]>> Reply-To: <[email protected]<mailto:[email protected]>> Date: Saturday, February 17, 2018 at 1:48 PM To: <[email protected]<mailto:[email protected]>> Subject: Re: [M100] DVI help That is interesting. I have just confirmed that there is continuity from pins 1 & 40 on the M100 end of my DVI cable, all the way to the + side of C67 inside the DVI, And continuity from pins 2 & 39 all the way to the - side of C67 (and every other ground in the dvi, including the case) C67 is a small electrolytic cap on the main motherboard of the dvi, front-left corner right next to the end of the CN1 ribbon cable. That makes C67 an easy place to measure this voltage while the cabe is connected and while everything is up & running. It's easy to see, and easy to get at with multimeter probes. So you can check the following: First check the M100 by itself for reference to see how everything else deviates from there. Without any cable connected to the M100, and the M100 turned on, I get 5.09v on pins 1 & 2 (red to pin 1, black to pin 2) on the empty M100 bus connector. Then with the DVI connected. With the cable connected and both the M100 and DVI turned on, I get 5.08v to 5.09v across C67. Black on the (-) side, toward the front of the DVI. With the DVI turned on but no M100 connected, I get 4.54v across C67. With the DVI turned on, and the cable connected to the M100, but the M100 turned off, I only get 0.83v across C67 This was all with the M100 just running on batteries. -- bkw On Feb 17, 2018 2:05 PM, "Fugu ME100" <[email protected]<mailto:[email protected]>> wrote: How are the M100¹s powered? AC or battery? The DVI box relies on the +5V from the M100 to enable the interface without that nothing will happen. You might want to check that both M100¹s are providing a good +5V at pins 1 and 40 on the IC Bus socket. Even though the M100¹s are working they can work down to about 4.5V or slightly less. Do you know if the DVIs boxes were working when they were purchased? The other bad possibility is that both DVI bus interfaces are dead :( It is the weakest link in the chain and they might of both died, on two units it should be very unlikely. However there is an electrolytic cap on the DVI interface board that connects to the +5V from the M100. It could of leaked and now be pulling the +5V down just enough to prevent the DVI interface buffers enabling. The rest of the unit would not be affected at all by this problem. Do you notice any changes on the M100 when it is plugged into the DVI? Sometimes when the +5V is getting loaded you can hear a whine from the on board power transformer as it struggles to supply power - at least on my M100 :-D On 17/2/18, 8:24 AM, "M100 on behalf of Randall Kindig" <[email protected]<mailto:[email protected]> on behalf of [email protected]<mailto:[email protected]>> wrote: >Ok, I¹m at my wit¹s end here. I have tried everything now and can¹t get >the DVI to work. > >Here¹s what I have: >- 2 M100¹s, 1 with 24K and and 1 with 32K >- 2 very clean DVI boxes with a single drive >- 2 DVI to M100 cables >- 2 DVI boot disks > >The cables have been tested by the guy who made them. So have the boot >disks for the DVI. There are 2 boot disks for backup. > >The M100¹s both work great. > >Here¹s the steps I take: >- connect the cable from the M100 to the DVI. I¹ve double and >triple-checked that the cable connections are solid and correct on both >ends >- connect a monitor to the DVI >- turn on the monitor >- turn on the M100 >- turn on the DVI without a disk >- when it asks for the disk, put it in and close the drive door >- the DVI boots to the Microsoft screen >- press RESET or CNTL-BREAK-RESET on the M100 >- NOTHING HAPPENS > >This is extremely frustrating. I bought 2 of everything just to rule out >where the issue could be and yet it makes no difference. > >I just bought a new DVI, thinking that was the issue because I have 2 of >all the other pieces and couldn¹t get it to work. It acts exactly the >same way as the first DVI. > >I¹ll buy a beer for anyone who can help me figure out what¹s happening >here :) > >thanks > >Randy >
