Apple IIE won't boot

I haven't really had a good look at this yet but I'd appreciate help on where to start looking.

I have an Apple IIE that won't boot up. It produces horizontal lines across the screen and won't beep when the power is switched on. I've checked the power supply and it's putting out the correct voltages. I have an enhancement set of chips on order (a 65c02 and new roms) so I'll be able to determine wether the roms and cpu are faulty. I'll post pictures of the problem soon.

Cheers Trev

So am I.

I'd like to get both boards working. I've been told that it could be roms or ram. When I get time I'll break out the eprom programmer and learn how to check the roms and ram.

I have an Amstrad NC100 that needs a keyboard repair, parts are on their way and the Apple IIe and disk II drive to go. Then it's back onto the Hankins.

Can you post a pic of the horizontal lines.. I had something similar and it was a faulty ROM.

 

I've made some notes at the time so I'll find them and let you know if its looks the same and which ROM it was.

Here you go and thanks.http://uploads.tapatalk-cdn.com/20160728/3ad6c0c05c82cc075af8dca40dd88fb2.jpg

The cpu is getting warm?

Ok I've changed boards to the 1982 one and changed the 6502 cpu but both cpus are getting hot and doing the same thing on the screen. I swapped roms one at a time and this happened.http://uploads.tapatalk-cdn.com/20160728/9d10ef16e151776edd25e6b108a36463.jpg.

I don't have time to get the eprom programmer to check the roms or the oscilloscope out at the moment as I'd like to go through it step by step. I'll wait until the enhanced rom and cpu set turn up and change the ic sockets before I do anything else. I'll probably change the video, tape and game connectors too as they're corroded. Then with all the socketed ICs removed I'll check the voltages to each one before I do anything else.

I did a bit on this today. I started by removing all of the socketed ICs as I'm going to replace all of the sockets. http://uploads.tapatalk-cdn.com/20160729/804bf711061038bdf20c7ae02d4a5d52.jpgThe leads on some of the socketed chips were heavily tarnished, not green but a dark grey, so I thought I'd change the sockets too just to be sure they're clean when I put the new Roms and cpu in and to eliminate any potential problems they might cause with the other chips.

I've got to say that this was made so much easier with my Rhino desoldering station, it doesn't get every component leg to come completely loose all the time but it does get the majority. One thing to remember is to keep the tip and suction airways clean, I push the cleaning rod down the element tube after desoldering roughly every 20 pins and clean the tip on the damp sponge every time I remove and replace the gun in its holder.

First I add a little solder to the board,http://uploads.tapatalk-cdn.com/20160729/f791cdda8a7043e7bbceefd7295d4111.jpg I think you can see the pins I've done here. Then I desolder the legs and pry the sockets off with a flat screwdriver. Be very careful not to jam the driver into the board just hook it under the socket if possible.http://uploads.tapatalk-cdn.com/20160729/47fc28af51a76f21c8b6a6be813b401c.jpg So here are the results http://uploads.tapatalk-cdn.com/20160729/ec1d918eae9c9893ec18b912dff39eb1.jpg with no damage to any tracks. It's probably a good time to check for broken traces too. The pile of dead sockets are shown to the right.

A close up of one section of the board.http://uploads.tapatalk-cdn.com/20160729/064ebfb69a95b6a1d695ba476d3d4306.jpg

The next step will be to get a toothbrush and some isopropyl alcohol and give it a clean before soldering new sockets on.

One question I have is should I socket the RAM while I'm at it or just let sleeping dogs lie? I was going to test them if I took them out?

Cheers Trev

Edited July 30, 2016 by BIG Trev

I've removed the ram chips and soldered all the sockets in, tested the TTL ICs, they all checked as ok so I reinstalled them along with the rest of the chips except the cpu, roms and ram. I'm still trying to work out how to check the roms and ram on my programmer.

To be continued...

After I've reread the instructions.

I think I've got it sussed. As I have two sets of roms that are supposed to be identical I've loaded them one at a time into the programmer's buffer and verified the second one against the data in the buffer. Two don't match which should mean one of each is faulty I just need to find files on the net to compare them against to see which one is bad or if both are. That's a job for tomorrow.

Great job..

 

I checked my notes... the similar horizontal screen I had was actually faulty ram so it's definitely worth checking them.

I've got a bit of time today so I checked the roms in the wellon vp390 and tried to read them. Out of the two sets of three roms I could only get one chip to read.

I'll know if this is the problem when my new roms arrive. I've put the ram back in for now as I can't seem to find them in the tester list. There are mT 4264-20 chips on one board and Hitachi 21-18470-01 on the other.

Cheers Trev

Edited August 4, 2016 by BIG Trev

Well that's a first. I just programmed my first ROM using the Wellon. I might have to get some more 2764 roms and make a set for the second IIE board. Then I'll have one standard board and one enhanced.

Cool bananas.

Well it seemed that a combination of new EF rom and 2 x ram chips plus a lot of cleaning of IC legs equals a working Apple IIe.

I did learn one other lesson. An Apple IIE won't boot unless you have the keyboard plugged in.

It only took me an hour to work that out. Now I need to have a look at the disk drive for it.

This is the Disk ][ analog card from the drive. http://uploads.tapatalk-cdn.com/20160824/57e2edaa4b63f65122c76489f5b5eef2.jpg

I don't know if you can see this but there looks to be some burnt pins and the socket has melted around them on this 74ls125 ic? The caps check ok, ie no shorts. I wonder if this has been plugged into the drive controller board incorrectly as those pins go to the header for the cable that goes to to card?

A fried 74LS125 is definitely a symptom when the cable is not plugged in correctly... however in my experience it's the one on the disk drive II analog board.

Not sure about the drive yet. It may be a speed or alignment issue. I just had another Ram chip fail but we're up and running again.http://uploads.tapatalk-cdn.com/20160825/91614e9ef9427523c2c3dd91ef618a23.jpg

I was lucky enough to be able to pick up an original full height drive, a clone full height drive and a half height drive from @lentitude, thank you sir, so I've had a play with them and my original drive today.

Firstly I cleaned the new Apple drive, case and heads and it worked straight off the bat. The half height was grubby on the outside but clean inside so I just plugged it in and it worked, I'll clean and maybe repaint this later.

Looking at the full height clone drive it has exactly the same Shugart mechanism and motor speed control board as the Apple drive even the control board was the same circuitry just not branded Apple.http://uploads.tapatalk-cdn.com/20160906/b1a231b90eaf2736e4d03df3878615a4.jpgthe clone is on the left. There are some slight differences in the case but you'd have to look closely.

I had made a new cable for my original drive and set the speed. The underside of the motor has a printed disc with black and white segments. I think you're supposed to get a strobe light set to 50 or 60hz shine it on the disc and it appears to stop rotating when you hit the correct speed. I don't have a strobe light but did read that you can do it under normal house lighting. I tried this and bugger me it worked, it's probably not as clear as if I'd used the strobe but you can see when you've hit the right speed.

I kind of cheated now in that I just swapped the four chips from the clone and an electrolytic cap with my drive rather than test one at a time with the probe or scope, plugged it in and it works.

So now I have an Apple II Europlus with two original drives and an Apple IIE with two original drives and both have original controller cards. I also have the clone half height drive with a clone controller card that works too. I'll use this for testing in future.

I will get the full height clone drive going one day. Maybe Friday after I've cut the grass, all 2 acres of it.

Cheers Trev