+dhe Posted July 27, 2021 Share Posted July 27, 2021 I had this Horizon, it was modified for a PBOX with a switching power supply, unfortunately, at one of the fairs, it got plugged in to a no switching power supply PBOX. I don't remember the state it was returned in, Bud Mills had it for a while. I'm going to try to rehab this, the voltage reg is hosed, and the batteries died a long time ago.... A couple of things to note, the back, was labeled WARNING - No Voltage Regulators, also, the original owner was George Lett, a really nice guy from the Huggers Users Group. 2 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted July 27, 2021 Share Posted July 27, 2021 LMK if you need a 3000 manual. Quote Link to comment Share on other sites More sharing options...
GDMike Posted July 27, 2021 Share Posted July 27, 2021 (edited) It appears this has a two stack of '138 chips, and for some reason mine had a three stack. Of course mine has been stripped and needs to be Rebuilt. Probably should do it as a 3000 if I rebuild.....orrrrr, maybe just get a NEW ram disk altogether instead... decision decision... Edited July 27, 2021 by GDMike Quote Link to comment Share on other sites More sharing options...
RickyDean Posted July 28, 2021 Share Posted July 28, 2021 2 hours ago, dhe said: I had this Horizon, it was modified for a PBOX with a switching power supply, unfortunately, at one of the fairs, it got plugged in to a no switching power supply PBOX. I don't remember the state it was returned in, Bud Mills had it for a while. I'm going to try to rehab this, the voltage reg is hosed, and the batteries died a long time ago.... A couple of things to note, the back, was labeled WARNING - No Voltage Regulators, also, the original owner was George Lett, a really nice guy from the Huggers Users Group. The great thing is that all the chips are socketed, you should be able to test the chips in a mini pro or something to find any that are blown. Then the caps would be next, so on, so forth. Easy board to work on generally. 1 Quote Link to comment Share on other sites More sharing options...
+dhe Posted July 29, 2021 Author Share Posted July 29, 2021 This Horizon originally had 3xAA batteries sticky taped to the board, of course after 20+ they started leaking, so at some point where cut off. Fortunately, when I redid the battery holders for the other horizon I ordered extra (.22 for the holder, and 9.99 for shipping). Today I worked on getting the old tape off, I read, moistening with WD40 helps, so I did that, and will give it overnight to see in and hopefully under. I did a preliminary position of the battery holders, even moving them as close as possible to the memory chips, they will still stick over the board maybe 1/16 or 1/32. Will that matter, when I go to drop the PBOX lid? I think, before playing with the batteries, I will spot check some of the chips with the 866. Quote Link to comment Share on other sites More sharing options...
+dhe Posted July 29, 2021 Author Share Posted July 29, 2021 And there was this little GEM from the Horizon 3000 Manual: ☛Running the card without all three NiCad batteries in place may cause damage to the memory chips. Quote Link to comment Share on other sites More sharing options...
+dhe Posted August 4, 2021 Author Share Posted August 4, 2021 I invested about 2 to 3 hours getting the old tape off. I'd dab a little w2 on a q tip on top of the old tape, then use this tool like a knife wittling on branch and scrape a little old tape off (rinse/lather repeat). This tool is pretty handy, it's strong enough to use for stuff, but not sharp enough to gouge or leave slice marks... 2 Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted August 4, 2021 Share Posted August 4, 2021 6 minutes ago, dhe said: Seriously worth the entire kit. 3 Quote Link to comment Share on other sites More sharing options...
+dhe Posted August 27, 2021 Author Share Posted August 27, 2021 I'm almost done testing chips, most of them have passed the TTL test on the 866II. On a side note, I did an upgrade to the 866II - the old version used to let me search by typing 74HC256. The newer version (and I might have done something wrong) - will only find chips, if I type 74256. Most of the chips check out, and I have replacements coming in for the rest. I also know from careful reading of the Horizon 3000 manual, do not insert ramdisk without all 3 batteries in place as damage may occur.... I looked at the pinouts for the 7805. I believe the test should look like" probe input to common - I should get something like 12V? Then probe common to output - should get ~5.5V? Then I should pick a couple of chips and test power and ground and get something like 5V? Does that sound like a plan, or is there a better plan, and or am I doing something wrong? I also am going to try making microclips to alligator clips, that way I can get everything hooked up and then power on the system and take readings, instead of actually having to touch something under power. A plea to those creating hardware. Designated test points on PCB's are a real luxury. Quote Link to comment Share on other sites More sharing options...
+dhe Posted August 27, 2021 Author Share Posted August 27, 2021 Does anyone know where I can get 7805 heat sinks with the locking screw/nut? Last I bought some was at a radio shack about 20 years ago? Quote Link to comment Share on other sites More sharing options...
HOME AUTOMATION Posted August 28, 2021 Share Posted August 28, 2021 Something's wrong with these??? 5pcs 19*15*10mm Black Anodized Aluminium 781/7805 Heat Sink For TO-126 TO-220 Plus+ these are made of Aluminium!✈️ 1 Quote Link to comment Share on other sites More sharing options...
+dhe Posted August 28, 2021 Author Share Posted August 28, 2021 Nope that is exactly what I took a picture of. BUT, I'm looking either for these with a screw and locking nut, or the screw and locking nut separate. Quote Link to comment Share on other sites More sharing options...
GDMike Posted August 28, 2021 Share Posted August 28, 2021 I think for practical purposes these are used frequently. I've seen painted aluminum heatsinks used, after awhile the paint comes off, but they still do the job. Quote Link to comment Share on other sites More sharing options...
HOME AUTOMATION Posted August 28, 2021 Share Posted August 28, 2021 Aluminum Heat Sink TO-220 w/ Threaded Stud, Lock Washer, Nut for Power Tabs 3 ea I've seen better prices though. Quote Link to comment Share on other sites More sharing options...
HOME AUTOMATION Posted August 28, 2021 Share Posted August 28, 2021 Don't know if you need these... Set of TO-220/7805 heat sink Washer /w Silicon Insulation Pad 24pcs Quote Link to comment Share on other sites More sharing options...
+dhe Posted August 28, 2021 Author Share Posted August 28, 2021 My past experience has been that these heat sinks: Will work with the component layout of almost any TI card. These: Will often times NOT fit (they bump in to things on the board). I guess I need to pull a screw and nut off an existing board and figure out the right specs for each and order the heat sink and screw and nut separate. I saw the silicon pads, what I had done in the past, was a thin coating of thermal paste between the back of the regulator and the heat sink, then tightened them down. I'm guess the silicon pad is if there is some fear of shorting, because I don't think silicon conducts heat very well.... Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted August 28, 2021 Share Posted August 28, 2021 Let me look in my screw/nut box, as I keep a lot of properly compatible screws handy. I usually buy mine in bulk from a US factory. . .because their prices are good and the parts are high quality. 1 Quote Link to comment Share on other sites More sharing options...
+FALCOR4 Posted August 28, 2021 Share Posted August 28, 2021 21 hours ago, dhe said: A plea to those creating hardware. Designated test points on PCB's are a real luxury. I'm with you on that! Test points along with Ksarul's PEB extender board would make troubleshooting much easier. 1 Quote Link to comment Share on other sites More sharing options...
+FALCOR4 Posted August 28, 2021 Share Posted August 28, 2021 4 hours ago, dhe said: My past experience has been that these heat sinks: Will work with the component layout of almost any TI card. These: Will often times NOT fit (they bump in to things on the board). I guess I need to pull a screw and nut off an existing board and figure out the right specs for each and order the heat sink and screw and nut separate. I saw the silicon pads, what I had done in the past, was a thin coating of thermal paste between the back of the regulator and the heat sink, then tightened them down. I'm guess the silicon pad is if there is some fear of shorting, because I don't think silicon conducts heat very well.... You might try nylon screws, washers and nuts. I bought a bag each off of either EBay or Amazon a couple years ago and they work great. I purchased the bolts a bit longer than they need to be so I can clip them down once installed. The silicon pad, probably used for the 7912 to electrically insulate the heatsink since the tab is at -12v, IIRC? 1 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted August 28, 2021 Share Posted August 28, 2021 19 hours ago, dhe said: Does anyone know where I can get 7805 heat sinks with the locking screw/nut? Last I bought some was at a radio shack about 20 years ago? I've never used the locking nuts or washers and they all seem to hold tightly. I did learn long ago that the nut size should be large enough so that it cannot rotate when you turn the screw. The last time I needed to refresh my inventory, I went to a smaller, local hardware store where they stocked all varieties of screws and nuts - I brought the the heat sink along to match the outer diameter properly. Be sure to add a small amount of thermal grease between the regulator and heat sink - a small mount goes a long way - so that the heat transfers to the sink, not to the board/components. There was a time when people were only/also adding thermal compound between the heat sink and the board and that contributed to the mask scorching/deterioration and some component failure. 4 Quote Link to comment Share on other sites More sharing options...
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