macintosh II not starting up or displaying

[newbmac2k12]

Over the past couple of months i recently got 2 macintosh II's complete, with hds and floppy drives as well as video card.  Of the two one has the tiny silver cylinder looking caps, the ones notorious for leaking.  The second has a newer revision board, i guess, that has the flat rectangular tantalum caps and only a few axial capacitors mounted horizontally.  Anyway both boards dont have battery leakage and i even cut the batteries out immediately to prevent it.  So of the two im trying the newer looking board.  I read about the jump starting it with a new pram battery.  What i did is purchase two new pram batteries with leads on them and using aligator clip wires clipped both new batteries to left over solder leads on the board where the old batteries were.  I can plug it in and hit power it starts up.  Well sound wise as i get a chime and the hd makes noise like its loading.  Since i dont have a mac monitor im using a lcd flat screen with the mac to vga adapter by belkin.  No video, so I thought maybe the video card so i used another from the other mac as both video cards are macintosh II video cards, the stock ones i guess.  No change, so from what i read it might be the fact of refresh rates or signaling since im using a mac 2 vga converter.  I have it in 13" rgb mode, switch wise, and the last time i used this adapter was on a pm 6100 i have and then a mac II si.  At that time the adapter worked.  So im out of ideas as to why no video display?

thanks in advance

 

[Macdrone]

Well just information there are radial caps that fail on the video cards so recapping may fix if setting the adapter does not work. I would also recap motherboard while at it.

 

[unity]

Just because the adapter works on the 6100 does not mean it will work on the II.

FYI - The one with tat caps is probably the older. Look at the revisions. The first batch did not have electrolytic caps, but those boards were recalled and sorta hard to come by. The later boards got electrolytic.

 

[RalfK]

Since i dont have a mac monitor im using a lcd flat screen with the mac to vga adapter by belkin.  No video, so I thought maybe the video card so i used another from the other mac as both video cards are macintosh II video cards, the stock ones i guess.  No change, so from what i read it might be the fact of refresh rates or signaling since im using a mac 2 vga converter.  I have it in 13" rgb mode, switch wise, and the last time i used this adapter was on a pm 6100 i have and then a mac II si.  At that time the adapter worked.  So im out of ideas as to why no video display?

The capacitors are mentioned before. But the other problem could be that the lcd isn't able to use the video signal from the old mac card. (Win-)DOS-PCs never used these H-Sync and V-Sync frequencies. There were even a lot of Multisync monitors which were not able to sync to mac frequencies. Try another video card or another flat screen. Video cards built by RasterOps or Radius would be my first choice (running at 1024*768 or 800*600) for testing, or Formac or Villagetronic from Germany. These were popular here.

Which card are you trying? Probably you can identify your cards:

http://www.cls.ne.jp/fujino/Nubus/          (the pictures and the names can be recognized .... )

 

[Elfen]

If it works on the Mac IIsi, it should work with the Mac II. Go back and get it working with the IIsi and then switch it to the Mac II. Make sure the video card is tight on the board, they do get loose on the socket.

If not, it's time to get the video card recapped. Just like the Mobo. But since the Mac II starts up, the culprit looks like an iffy video card. Though recapping the video card is the same as the Mobo, I have not seen anyone doing it. I think Uniserver might do it - ask him. Depending on the video card, it is usually about 10 caps to replace.

 

[RalfK]

If it works on the Mac IIsi, it should work with the Mac II.

That's right.

Sorry, I only had read PM 6100.

 

[newbmac2k12]

well heres an update, i finally got around to trying something on it.  I got out an old dell big crt monitor.  If i remember right it supported up to 1280x1024.  Anyway i hooked up the system to it and bingo got a picture with a flashing floppy disc.  This is on the board that has the smt capacitors.  The hd makes a clicking sound, so i think that is shot.  So since i have another spare II that came with a 3 1/2 in hd not the bigfoot quantum this one has, ill try that hd.  Plus I now just need to get ahold of or make a set of system 7.5 disks for it to do a fresh install. So i guess it was the flat panel and its signaling versus the old crt one.

 

[uniserver]

can you take pictures of these main boards…..     So far all i am aware of, is the earlier Macintosh II boards with all Axial caps,  

and then later on they started using SMT cans… most of the axial ones are still wroking. 

most of the SMT can boards are destroyed from cap goo trace rot … yada yada

 

[newbmac2k12]

to uniserver, the board in the top pic is the one i am currently working on, its the working one.  On the other mac II i have the board pictured on the bottom.  One thing though, i think i read somewhere in this thread or site, that the top board not only being the early ones, but had issues and was recalled. Why was that board recalled specifically?

Thanks.

 

[unity]

I said that up top. Recalled because of a socket issue. The four chips to the lower right, see those? The black upper right one comes in versions that have different pin layouts underneath - the HMMU (Memory Management Unit). Important if upgrading to a PMMU which would not fit. When Apple made the first short run, the socket was specific to the chip they used so upgrading was impossible without soldering in a new socket. Without a PMMU, the Mac II can not use 4MB SIMMs.

It gets even more complex since there are two sets of SIMM banks and they are not the same. If you dont upgrade the ROMs for Superdrive support, bank A can not even use high-density SIMMs. Its really an odd Mac. I got around most of that by just putting in an 030 Daystar upgrade.

 

[unity]

OVERVIEW
A limited number of Macintosh II CPUs were manufactured with an HMMU-unique
socket that does not allow the CPU to function properly if a PMMU upgrade is
installed.  Customers who install a Finished Goods PMMU Upgrade Kit in a
Macintosh II with an HMMU-unique socket are entitled to a Macintosh II Logic
Board exchange at no cost.
 
HOW TO IDENTIFY AN HMMU SOCKET
To identify whether the system contains an HMMU-unique socket, look at the
underside of the Macintosh II Logic Board.  (Refer to your Module
Identification manual for the location of the HMMU/PMMU on the Macintosh II
Logic Board.)
 
* HMMU sockets, which accommodate HMMUs only, contain 70 gold contacts soldered
  through the board in a random pattern.
 
* HMMU/PMMU sockets, which accommodate either component, contain 132 gold
  contacts in a 13 by 13 pin pattern.
 
When a PMMU upgrade is installed in a Macintosh II CPU containing an
HMMU-unique socket, many pins do not connect and the system will not boot.
 
REPAIR EXTENSION AUTHORIZATION
To obtain Labor, Parts Credit, and Parts Margin reimbursement,* return the
Macintosh II Logic Board to Apple and record the part number on the SRO form.
In addition, record the repair extension authorization code "OMR2560" in the
Warranty Information section of the SRO.
 
If a logic board with an HMMU-unique socket is covered by AppleCare and meets
the criteria for this program, list the exchange transaction under the Repair
Extension Program on the SRO, not under AppleCare.

 

[newbmac2k12]

@ unity, ok i took the board out and counted it, i have the 132 pins or a 13x13 row setup.  I doubled checked and they are soldered through.  One thing though, if this originally is a hmmu setup, then i guess since the other smd cap board is waiting for a recap, couldnt i just take its gold capped pmmu module out and use it for this board to give it that upgrade?  Im assuming the black one is the hmmu and the motorola one with the gold square on the other is the pmmu type?  Finally, as for the superdrive, I guess on the rom issue I wont find that out unless i get an os on it, hence making a set of sys 7 disks on hd disks, and booting from it right?  I mean if it doesnt boot of a hd diskette but a 720k one then i only have the original roms right, the ones for the 800k drives?

Thanks

 

[unity]

Yes, you can swap that over no prob. I forget if I did, but I may have done the same from a IIx. With my 030 upgrade, it really did not matter in the end since I had to pull the chip for the upgrade anyway.

Correct on ROM. But I am pretty sure just the floppy ROM has to be upgraded. Check the other board! I think its a small square one that fits into a bowl socket. If you look at the pics, its the two different sized square chip in those brown sockets. One or both have to be upgraded. I dont have the detail on me.