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Simasimac SE/30 Diagnosis
- Thread starter dcr
- Start date
Yes. I'll try to get one tonight or tomorrow. It's basically 8 columns of floppy, 8 columns of gray, 8 columns of floppy and 8 columns of gray.
Should be VRAM or video-address related then.
U[A..D]8 are the video address muxers. They generate the address signals for the two VRAMs.
Data input to the VRAMs comes directly from the 030 bus. Data output from the VRAM is fed into the shift register at UE8 from where it is put out in serial to the PAL at UG7.
The problems lies somewhere before the video data reaches UG7.
Do you have a chip tester? I usually desolder all seven U*8 chips and run them through a tester. Takes a few minutes and tells me for sure if I am looking for a bad trace somewhere or not.
U[A..D]8 are the video address muxers. They generate the address signals for the two VRAMs.
Data input to the VRAMs comes directly from the 030 bus. Data output from the VRAM is fed into the shift register at UE8 from where it is put out in serial to the PAL at UG7.
The problems lies somewhere before the video data reaches UG7.
Do you have a chip tester? I usually desolder all seven U*8 chips and run them through a tester. Takes a few minutes and tells me for sure if I am looking for a bad trace somewhere or not.
Thanks. I found one on Amazon and added it to my private wish list.
I took a hot air gun to the board to see if remelting the solder connections would have any effect. It didn't.
Some of the legs (on the sides facing the caps) on UE8 and UI12 look dirty or possibly corroded. Maybe this weekend I can try cleaning them and looking at that with the magnifying glass to see if any of the legs are broken due to corrosion. Doesn't appear that way now but who knows what could be going on close up.
I took a hot air gun to the board to see if remelting the solder connections would have any effect. It didn't.
Some of the legs (on the sides facing the caps) on UE8 and UI12 look dirty or possibly corroded. Maybe this weekend I can try cleaning them and looking at that with the magnifying glass to see if any of the legs are broken due to corrosion. Doesn't appear that way now but who knows what could be going on close up.
Bolle did you get one of the sets that comes with a variety of sockets? (dcr, please pardon me for a moment while I hijack the thread for two postings). I'm looking at this on Ebay (may have to use the drop down next to "model" and for $113 that looks mighty attractive.
https://www.ebay.com/itm/TL866II-PLUS-Programmer-EEPROM-Support-NAND-Flash-AVR-MCU-GAL-PIC-SPI-25-Adapter-/232489072939?_trksid=p2385738.m4383.l4275.c10&var=532270259941
Hmmm. Using dcr's mention of Amazon, this looks like it may be the same and $13 cheaper
http://a.co/gVeAFMX
although the description says 21 adapters instead of 25. Oops, that's the CS instead of the II. The CS is discontinued. The II is "improved".
Here, on Amazon, for about $2 more than Ebay:
http://a.co/3bVkbgy
After careful examination, it appears the Ebay package comes with a 1.8V adapter and a dedicated green TSOP48 socket, which the Amazon ;package lacks.
Bolle any comments, suggestions, hints on these choices. Feel free to use PM or start a new thread, so we don't continue my hijacking too long.
I have an old Needham EMP-30 which was an excellent programmer in its day. But Needham has been out of business for years, so no support for new chips and the price of the entire TL866 compares favorably with what I might spend when I'm lucky enough to hunt down a package adapter I don't already have for the EMP-30.
I suspect the EMP-30 still supports more devices, but again, nothing new...
https://www.ebay.com/itm/TL866II-PLUS-Programmer-EEPROM-Support-NAND-Flash-AVR-MCU-GAL-PIC-SPI-25-Adapter-/232489072939?_trksid=p2385738.m4383.l4275.c10&var=532270259941
Hmmm. Using dcr's mention of Amazon, this looks like it may be the same and $13 cheaper
http://a.co/gVeAFMX
although the description says 21 adapters instead of 25. Oops, that's the CS instead of the II. The CS is discontinued. The II is "improved".
Here, on Amazon, for about $2 more than Ebay:
http://a.co/3bVkbgy
After careful examination, it appears the Ebay package comes with a 1.8V adapter and a dedicated green TSOP48 socket, which the Amazon ;package lacks.
Bolle any comments, suggestions, hints on these choices. Feel free to use PM or start a new thread, so we don't continue my hijacking too long.
I have an old Needham EMP-30 which was an excellent programmer in its day. But Needham has been out of business for years, so no support for new chips and the price of the entire TL866 compares favorably with what I might spend when I'm lucky enough to hunt down a package adapter I don't already have for the EMP-30.
I suspect the EMP-30 still supports more devices, but again, nothing new...
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Does anyone have a link to a closeup image(s) of broken/rotted traces? The ones I found in a search weren't very informative. I looked the board over with a magnifying glass and didn't see any obvious trace problems but I'd like something to compare to to make sure I'm not overlooking more subte details that might be indicative of a problem.
The older discontinued 866CS might be a better option than the newer one.
I did not look this up in detail but I think I read somewhere that the newer one does not support some older chips that need a higher Vpp (the old one does 21V, the new one tops oht at 18V or even lower)
If you want to programm older EPROMs that need higher voltages you might want to go for the older model.
I got mine on a sale somewhere and it did not include as many adapters as both of your choices. I did however get one of those 25 pieces adapter sets separately - never used most of them.
Those clip thingies for SOP/SOJ packaged never work too well for me as mostly the legs of the ICs I am checking are partially corroded and/or contain residue flux from desoldering them which makes for bad contact. I tend to just solder them down on the flat non-clip adapter most of the time.
I got a few more of those adapters.
I did not look this up in detail but I think I read somewhere that the newer one does not support some older chips that need a higher Vpp (the old one does 21V, the new one tops oht at 18V or even lower)
If you want to programm older EPROMs that need higher voltages you might want to go for the older model.
I got mine on a sale somewhere and it did not include as many adapters as both of your choices. I did however get one of those 25 pieces adapter sets separately - never used most of them.
Those clip thingies for SOP/SOJ packaged never work too well for me as mostly the legs of the ICs I am checking are partially corroded and/or contain residue flux from desoldering them which makes for bad contact. I tend to just solder them down on the flat non-clip adapter most of the time.
I got a few more of those adapters.
Thank you, Bolle.
Yesterday I did a google search on difference between the 866CS and 866II and a nice blog posting came up with a table of features for the various models. It did show the 18V vs. 21 or 22V for Vpp that you mention. Most of the time, I'm programming modernish flash to put in place of old EPROMs. The Vpp shouldn't be needed to read the old EPROMs. In my particular case, if the issue does come up, I can probably program the older stuff on my EMP-30. Fortunately, the old chips are usually DIP or PLCC. No need for the fancy sockets.
DCR, you might search for some of techknight's postings. He's done a lot of board level repair and diagnosis, or even PM him.
In my experience, which is not very extensive, just really old, the board rot is usually at vias and solder pads. Vias are the solder fillled holes through the circuit board which connect traces on the back with traces on the front. And solder pads, are, of course, where pins from components are soldered to the board. On most of the board, the traces are covered by solder mask (the green coating) and so are protected. It takes a pretty nasty level of corrosion to reach under the solder mask, but perhaps it can seap in from the edges at solder pads.
Anyway, for vias and soldered joints, the solder should be relatively hard. I found that poking at vias and joints near leaky capacitors with an implement like a dental pick reveals soft solder which has been corroded but is not especially visibly distinctive. Then one can focus one's continuity testing in those realms. Although in some cases one probably just needs to llok at the schematic, hook a probe up to each address and data line in turn, and confirm that they're all connected to all the components they should be.
In my case, back around '97 I had a dead IIci. Poking with a pick, I found a soft via. Turned out the copper lining was eaten right out. But the top and bottom traces were obvious (happily no connection to an interior layer). I traced the connections back to their exposed end points and ran a bit of wire wrap to bypass the damage, and the board worked for many years after that. Eventually, the plastic SIMM sockets disintegraded, so if I ever want to use that one again, I'll need to replace the SIMM sockets.
Yesterday I did a google search on difference between the 866CS and 866II and a nice blog posting came up with a table of features for the various models. It did show the 18V vs. 21 or 22V for Vpp that you mention. Most of the time, I'm programming modernish flash to put in place of old EPROMs. The Vpp shouldn't be needed to read the old EPROMs. In my particular case, if the issue does come up, I can probably program the older stuff on my EMP-30. Fortunately, the old chips are usually DIP or PLCC. No need for the fancy sockets.
DCR, you might search for some of techknight's postings. He's done a lot of board level repair and diagnosis, or even PM him.
In my experience, which is not very extensive, just really old, the board rot is usually at vias and solder pads. Vias are the solder fillled holes through the circuit board which connect traces on the back with traces on the front. And solder pads, are, of course, where pins from components are soldered to the board. On most of the board, the traces are covered by solder mask (the green coating) and so are protected. It takes a pretty nasty level of corrosion to reach under the solder mask, but perhaps it can seap in from the edges at solder pads.
Anyway, for vias and soldered joints, the solder should be relatively hard. I found that poking at vias and joints near leaky capacitors with an implement like a dental pick reveals soft solder which has been corroded but is not especially visibly distinctive. Then one can focus one's continuity testing in those realms. Although in some cases one probably just needs to llok at the schematic, hook a probe up to each address and data line in turn, and confirm that they're all connected to all the components they should be.
In my case, back around '97 I had a dead IIci. Poking with a pick, I found a soft via. Turned out the copper lining was eaten right out. But the top and bottom traces were obvious (happily no connection to an interior layer). I traced the connections back to their exposed end points and ran a bit of wire wrap to bypass the damage, and the board worked for many years after that. Eventually, the plastic SIMM sockets disintegraded, so if I ever want to use that one again, I'll need to replace the SIMM sockets.
I had some time today so I figured I would take a look at this board again. I went through it with a magnifying glass, checking the soldering connections on every capacitor I replaced. I also checked the legs on several components where it looked like corrosion might have caused damage but they were all solid. I re-soldered connections that seemed suspect. I also removed, re-fixed (hopefully) the pad that had come loose (last time) and re-soldered a capacitor that I didn't have complete confidence in.
And I made things worse.
The first boot seemed promising but the screen remained the same as before. But no floppy disk image now. I tried rebooting and this time heard the chimes of death and the screen remained the same. Took the board out and tried again. Checked all connections. Tried re-soldering the aforementioned worrisome capacitor and re-installed. No chimes of death but the screen is the same and still no sign of the floppy disk icon.
I'm thinking I'm probably going to end up sending this board to someone more experienced than me before I make things worse. I've already turned a passable soldering job into something less so.
And I made things worse.
The first boot seemed promising but the screen remained the same as before. But no floppy disk image now. I tried rebooting and this time heard the chimes of death and the screen remained the same. Took the board out and tried again. Checked all connections. Tried re-soldering the aforementioned worrisome capacitor and re-installed. No chimes of death but the screen is the same and still no sign of the floppy disk icon.
I'm thinking I'm probably going to end up sending this board to someone more experienced than me before I make things worse. I've already turned a passable soldering job into something less so.
techknight, If I get no chime with the original ROM, but I do with the ROM-inator, what should I check? I get the following pattern:
Attachments
I have that nasty vertical line screen or 4-5 seconds after I turn it on, then she chimes, screen turns normal, and she boots. These se/30's are nasty little creatures..
how long have you left it running? mine took a bit to figure it self out then booted and screen turned normal
Actually the first three times I got the simasimac screen for a few seconds, then it booted normally. But when I closed it and installed the back, no more clean boots, only the chime then simasimac screen, no matter how long I leave it running...
did you resolve yours?
