CDTV-SCSI Do-It-Yourself Sets - BULK ORDER
- Thread starter o.eschi
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As I posted, I ordered my own resistor networks from a local parts supplier. I double-checked that I ordered the right part.. and then, as I opened the packet, there were two correct resistor networks and two incorrect ones (yep, two more of those 9-pinnies! 
oh
As I wanted to test this thing, I put in sockets for the two 330 ohm networks, inserted the 9-pin parts and added two 330 ohm resistors and soldered an extra wire to complete the circuit. Ugly but works, at least for testing.
In the first post there is a link to german assembly instructions. What does it mean on the part "Antwort: SJ1 wurde gesetzt. Der schaltet den SCSI-Takt zwischen 16Mhz und 7 Mhz um. 16MHz sind eigentlich vom Treiber nicht vorgesehen, funktioniert aber trotzdem und ist schneller"? Google translation of that doesn't make sense. First I put the solder blod to the 16M setting (as it is in the picture) but it didn't work (boot shows grey and white screens but than halts at black screen).
Switching the setting to 7M I was able to boot my CDTV from a SCSI hard disk! The installation on the disk was a WB3.1 from an A4000 and it didn't boot correctly on a CDTV (no suprise) but I was able to access the HDD succesfully.
I put a Molex power splitter cable and took the power for the HDD from the CDTV's cd-drive's power cable. Seems to work (+5v line was around 4,92v with everything running) just fine. As I don't have any SCSI-IDE (and then IDE-Compact Flash) adapters to put inside the unit, I think I am going to put an external SCSI connector to the rear panel of the CDTV and use some external SCSI HDD box. Problem at the moment is that I don't have any extra SCSI HDDs.
Photos available here.
Again, thanks for producing this great little gadget, Olli!
ohAs I wanted to test this thing, I put in sockets for the two 330 ohm networks, inserted the 9-pin parts and added two 330 ohm resistors and soldered an extra wire to complete the circuit. Ugly but works, at least for testing.
In the first post there is a link to german assembly instructions. What does it mean on the part "Antwort: SJ1 wurde gesetzt. Der schaltet den SCSI-Takt zwischen 16Mhz und 7 Mhz um. 16MHz sind eigentlich vom Treiber nicht vorgesehen, funktioniert aber trotzdem und ist schneller"? Google translation of that doesn't make sense. First I put the solder blod to the 16M setting (as it is in the picture) but it didn't work (boot shows grey and white screens but than halts at black screen).
Switching the setting to 7M I was able to boot my CDTV from a SCSI hard disk! The installation on the disk was a WB3.1 from an A4000 and it didn't boot correctly on a CDTV (no suprise) but I was able to access the HDD succesfully.
I put a Molex power splitter cable and took the power for the HDD from the CDTV's cd-drive's power cable. Seems to work (+5v line was around 4,92v with everything running) just fine. As I don't have any SCSI-IDE (and then IDE-Compact Flash) adapters to put inside the unit, I think I am going to put an external SCSI connector to the rear panel of the CDTV and use some external SCSI HDD box. Problem at the moment is that I don't have any extra SCSI HDDs.
Photos available here.
Again, thanks for producing this great little gadget, Olli!
Oh, I didn't produce it - I only organize the bulk order in cooperation with MatthiasH (he produce it!). Please ask him for informations about the 16 mhz option. Normally you should use 7 mhz.
MatthiasH
New member
Hi,
the solder-jumper SJ1 switches the speed of the SCSI-Chip from 7 MHz to 16MHz. Usually this increases the performance dramatically and up to now I never heard of any problems. Theoretically the timings stored in the CDTV-ROM need to be patched aswell, but again: I never found any problems (up to now - I like to make my products better).
The original design of Commodore was based on the 7MHz. So I left this option for compatibility. I suggest you double check your soldering, especially for the oscillator, Pin 7 of the SCSI-Chip and the 74HCT245-buffer. The board definetly works at 16Mhz! If the probelm "magically" disapears and reapears, think of cleaning the expansion socket and the slot-contacts. The expansion socket was unused for decades and oxidated. Sometimes several replugs do the trick.
You can test SpeedGeeks softwarething for the 14Mhz A2091-Mod to set the correct timing parameters, too. It should work here, too. But it needs to be executed at every boot which is bad if the HDD does not show up at all.
I visit amibay only seldomly. So feel free to ask questions at a1k.org: Easy registation, great forum, registered users see several hidden areas with a lot of off-topic and funny stuff, which is hidden for giests and most of us speak english, too.
Fancy a VGA-graphic card for the A500? Fancy a Autoconfig-RAM/IDE board for the Harms-Turbo? Fancy a HDFloppyFix? Fancy a A600-1MB Chip PCB? Everything is there and we usually organize bulk orders quite frequently
.If there is a urgent request in this thread, please send me an PM to notify me about it. I get an email notification for pms.
With best regards
Matthias
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@o.eschi
Got my kits the other day - thankyou. But before they were sent I got two conflicting emails about some resistors maybe being wrong. Just thought I'd check on this. I was just wondering what resistors may be the wrong type? I really don't feel like going through 15 pages to find out
Got my kits the other day - thankyou. But before they were sent I got two conflicting emails about some resistors maybe being wrong. Just thought I'd check on this. I was just wondering what resistors may be the wrong type? I really don't feel like going through 15 pages to find out
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