TGB1718

Your only interested in Q3 which provides luminance (probably ok) and Q2 which provides Chroma. Don't know if you've got these, Page 3 has the video circuitry on it. Schematic_130xe_Jerzy_Sobola_Landscape.pdf

It's difficult to test transistors in-circuit, you usually have to remove them, then testing is easy. Put meter across Emitter and Collector set to either resistance (or diode test if your meter has this function), your should get open circuit. reverse the connections and again open circuit. If it's an NPN transistor, place +ve meter probe on the Base and in turn place the -ve probe on collector, then emitter you should get a resistance reading both ways. Now put the -ve terminal on the base and again in turn the +ve probe on collector and emitter you should get open circuit. For PNP the testing is the same across collector/emitter. but reversed for base to collector/emitter The video circuit appears to have two NPN transistors - 2N3904 here's the pinout Hope this makes sense.

The only pin guaranteed to have +5V on it is pin 8, the power supply pin, all the others are switching on and off at different speeds hence the varying voltages you are seeing. You will not be able to measure voltages on any of these pins with a voltmeter, you need a scope. Could be an MMU problem or Freddie chip

As good old Google tells you passive components are resistors, capacitors, inductors, essentially anything that's not a semi-conductor.

Had a look at the circuit diagram and chip datasheet and think this problem is caused by the data being removed from the data lines too early, look at this timing sheet, you will notice the "VALID OUTPUT" is still valid after the CE & OE go high and although this is a very short period, if the system is not reading until the end of the valid period, then a faster chip may have removed the data before it has been fully read. Why Cartridges are OK may just be down to the way the MMU handles access, without information on the internal timing of the MMU it's a bit difficult to see why Cart's are ok. This is my best guess why it doesn't seem to work with fast chips.

Had a look at the circuit diagram and chip datasheet and think this problem is caused by the data being removed from the data lines too early, look at this timing sheet, you will notice the "VALID OUTPUT" is still valid after the CE & OE go high and although this is a very short period, if the system is not reading until the end of the valid period, then a faster chip may have removed the data before it has been fully read. Why Cartridges are OK may just be down to the way the MMU handles access, without information on the internal timing of the MMU it's a bit difficult to see why Cart's are ok. This is my best guess why it doesn't seem to work with fast chips.

I keep an old PC with Windows XP just for this purpose, one thing I've found though is not many PC 3 1/2" drives will step past track 80, a lot of the images I make have just 80 tracks, generally not usually a problem though as long as the disk is not full. The software @ParanoidLittleMan has linked is awesome for this purpose.

Nice, will probably come here before Ebay, nice idea.

I use the USB one on Altirra and on my 130XE/800 setup, so 9 pin is not useful, also, has to be a gamepad for me as I find it difficult to hold joysticks (old age creeping in ). What I did was use an Arduino with a USB HAT, wrote some code and I can use my Buffalo Joypad on both, as a side effect, I enhanced the USB code to be able to use a USB Keyboard too through the joystick port (obviously not Joy and Key at the same time)

Got round to trying a few games, seems a bit hit and miss, Blood Money ran fine, so did Star Trek, a few others failed, but I find that quite a lot do that on STE's, so not a conclusive result. My STE is the same as your, 4MB RAM

@Wrathchild what a star, worked first time with no adjustments, even works with SDX, well done 😍

Thanks, unfortunately it's identical and doesn't run for me.

When I tried loading from SDrive-Max on my 800, it started loading, then SIO went mad, not loading anything, just a screaming SIO noise, then stopped ??? so maybe your right

Just tried on my 800 with Incognito installed, same result, also if trying to run under SDX always get the memory Conflict even with the 'X' option. @Mclaneinc Can you attach your working copy here, just in case it's something not "unzipping" correctly. I can do a compare and see if there's corruption in mine.

@Mclaneinc thanks for the advice, but also bear in mind I get the same result on a "real" stock 130XE, doesn't make sense Will try my 800 later