slaanesh

Right, yes the 9918 is a little different pinout to the 9928/9929. The big difference is in pins 35, 36 and 38 On the 9918 this is basically composite out AND colorburst clock (3.58Mhz CLK signal) On 9918 versions of the SG-1000, the computer uses both of these features, especially PIN38 which is the CLK for the CPU. PAL SC-3000s use the 9929 and pins 35,36 and 38 are the YPbPr signals used by TMS-RGB to generate the RGB data. Since the 9928/9929 doesn't supply the CLK signal, there is an external XTL on the PAL SC-3000 to do the job. Summary: If your SC-3000 already has 9929 (PAL versions), you can use TMS-RGB without mods... well you still have to mod the output connector, etc. If your SC-3000 already has 9918 (NTSC versions), you can't directly use TMS-RGB, you will need to do mods to your SC-3000 first and supply an external CLK for the CPU.

So regarding the above post, batari got in touch with me and it looks like my board has a faulty RAM chip. He has offered to replace my board which is really nice of him and testament to his awesome service - thank you!

I have had my Concerto for some time now and I can't get it to work reliably. Symptoms When I use the Concerto the menu sometimes starts, perhaps 1 in 12 times? When it does start it's usually the very first start for the day... and after that it will hardly start. When it doesn't, there is usually a little flicker at the very start but it's super quick and I can't see. There is no Atari logo. Then it sits at the black screen. What I've tried Two different NTSC Atari 7800s; both can play regular carts just fine first time, every time. One of these has an S-Video mod and new caps all round the other is vanilla. I've tried various of the firmware files, from latest to the earlier ones. I've tried it with and without a POKEY installed. I've tried various SD cards ranging from older 512MB all the way to 32GB, all formatted either FAT or FAT32 depending on their size. I'm using the latest EELOADER.BIN What I haven't tried I have a PAL Atari 7800 so could try that I'm a bit disappointed about the lack of reliability and I'm thinking no one else card is behaving like this?

Im still very curious to see what will become of the A8 version of Elite, I've got a PAL and NTSC machine ready to test this out as soon as it's release

I assume having a linear bitmap means a faster drawing algorithm. So combined with the faster MHz CPU should mean a version of Elite that is somewhat faster than the C64

Yea this is looking great thanks so much for the effort

So after changing to the 1-2450 all my 7800 carts now start first-time every-time. The concerto with the POKEY hardly ever starts, perhaps 2 in about a 20 attempts. The 1-2450 is getting about 9.5V input but 4.9V output, both measured directly on the pinout of the 1-2450. The output is a little low but within spec. I've had absolutely no issues with these for replacements in other machines and usually find them rock-steady. I don't have a 2-2450 handy but I do have an OKI 78SR-5/1.5 which does 1.5A output, I might try that one instead. EDIT: Also one other thing, it's not the UAV video mod, it's the Longhorn A/V Mod 2.1B - does this have a higher power requirement? I removed the 1-2450 and replaced it with the 78SR-5/1.5 - no real difference in performance other than a slightly higher output voltage of 4.93V. Concerto is still the same. I guess I could take the POKEY out again but my intention was to have a POKEY equipped concerto. I don't have a spare SALLY - well - or do I? I have myl PAL 7800 I guess if it's socketed I could borrow it to see if there is any difference.

I replaced the 7805 which was outputting 4.83v with a Traco TSR 1-2450 which is a nice switching voltage regulator. I also had already changed the caps previously. It still doesn’t come on reliably though regular commercial carts seem to start far more readily. it also has a UAV video mod but that would interfere I would think.

Dang it it turns out it's my NTSC Atari. It doesn't always switch on first go. It switches on, LED is on, but nothing happens. Just a black screen. Sometimes the same with other carts too but seems worse with the concerto. Power draw? Bad cap?

Just continuing on my previous post, I soldered a socket back on my Ballblazer cart and inserted the POKEY back into it and it has sound! So it's not the POKEY.

I have had a Concerto for a while and it works well with my relatively rare (well rare for Australia, usually PAL) NTSC Atari 7800 . I recently bought a PAL Ballblazer cart. I verified that sound worked on the game using my PAL Atari 7800. I removed the POKEY and I think the extraction went well, all pins good no breakages and no damage to the POKEY. I inserted the now loaded-with-POKEY concerto into the NTSC Atari 7800. Black screen! So I updated the firmware to the latest : hbios_concerto_0.96_build_72822_NTSC.bin I checked that it was successful and then re-inserted my POKEY into the concerto and tested again. Still black screen. My installation basically consisted of me inserting the chip into the socket (the correct way, all pins carefully checked, straight and in) - is there anything else that needs to be done? I see there is an empty JP1 under the socket where the POKEY goes. Maybe I fried my POKEY somehow? I'm pretty experienced removing ICs and have good soldering and desoldering skills and equipment.

Here is a sample of the output on my CRT. Galaga is on angle to reduce reflection but it's still present. But you get the idea... It looks really good! Ninja Golf Galaga (on angle, to avoid severe reflection)

Okay so a few years later I revisited this mod and looked at what I had done. I re-soldered most points as my soldering skills have improved considerably since. i then reviewed the installation documentation... I had made a mistake! OMG! I had mistakenly soldered the wires that are at R18 and R19 to R18 and R17 respectively! Do I feel foolish! My excuse is that I must have assumed the wires go on the place where the resistors were removed! The video quality is excellent with s-video!

My next task is to check on my scope what sort of activity exists on the lines going to the head whilst the drive is actively reading.

In the mean time I create a 1541 test cartridge from World of Jani and did an alignment test. It failed miserably. The 1571 cannot even read a single track. Could it be the alignment is that much out physically? Where to go from here? See the two photos, ran the test a few times here are a couple of the results.