Jump to content
dhe

This old Horizon #3

Recommended Posts

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.

 

 

 

backhr3.jpg

fronthr3.jpg

voltreg.jpg

  • Like 2

Share this post


Link to post
Share on other sites
Posted (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 by GDMike

Share this post


Link to post
Share on other sites
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.

 

 

 

backhr3.jpg

fronthr3.jpg

voltreg.jpg

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.

  • Like 1

Share this post


Link to post
Share on other sites

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.

batt1.jpg

batt2.jpg

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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...

 

image.thumb.png.7d4d34a6303a374711d6ba3152c62142.png

 

 

 

 

 

 

clean_bat.jpg

  • Like 2

Share this post


Link to post
Share on other sites
6 minutes ago, dhe said:

 

image.thumb.png.7d4d34a6303a374711d6ba3152c62142.png

 

Seriously worth the entire kit.

 

DSC00047.thumb.JPG.c91780a6a70834d2e1a3d6320956a881.JPG

  • Like 3

Share this post


Link to post
Share on other sites
 
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.

Share this post


Link to post
Share on other sites

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?

image.png.af843bef4389e68dc9076af298cd9bcb.png

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

My past experience has been that these heat sinks:

image.png.238391ada820372fe5da7c16bf4e1cdb.png

Will work with the component layout of almost any TI card.

 

These:

image.png.56f1516d6b5fb2b132c3175ecbb0e27e.png

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....

 

 

 

Share this post


Link to post
Share on other sites

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.

  • Like 1

Share this post


Link to post
Share on other sites
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.

  • Like 1

Share this post


Link to post
Share on other sites
4 hours ago, dhe said:

My past experience has been that these heat sinks:

image.png.238391ada820372fe5da7c16bf4e1cdb.png

Will work with the component layout of almost any TI card.

 

These:

image.png.56f1516d6b5fb2b132c3175ecbb0e27e.png

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?

  • Like 1

Share this post


Link to post
Share on other sites
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?

image.png.af843bef4389e68dc9076af298cd9bcb.png

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. 

  • Like 4

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...