getting started with your new HP 21xx

Glen wrote... Glen is spot on... that's the number one most common reason a system won't power up (or I should say, won't run - it'll still power up). Number two reason is probably incorrectly configured memory (controller, memory boards, or MEM module), including the very likely possibility that the large ribbon cable which connects memory to the controller isn't seated well or making good contact. Third reason is missing or improperly configured microcode (FAB, FEM, WCS, UCS, or mainboard jumpers), including the possibility that the FAB/mainboard/FEM cable isn't seated well or making good contact. If the system was delivered exactly as it was previously used without having been scrounged for parts or poked at by non-HPaware playbabies, the above list is wrong, there are more likely causes of failure. Viewing the battery connector plug from the rear, there are three rows of three pin sockets. You want your 820 ohm resistor across the outer pins of the middle row. Another thing I should mention... remove the power supply before you power up the machine. Very simple/quick to do, it was made for quick/easy replacement. Inside the supply was the ubiquitous black foam. It has probably crumbled and/or turned to goo. Take off the cover of the power suppy after removal and get rid of all that foam with a vacuum cleaner. Clean any messes (contact cleaner, toothbrush, etc.) up. Some advise just closing it back up at this point. I don't - that foam was glued to the top lid for very good reason. Those 4 or 5 power supply cards inside the supply - you do NOT want them touching the top of the metal cover :) Less impressive but equally destructive is if they come loose which the foam also prevents. I cut a piece of foam from air conditioner filter material (either 1/8 inch thick or 1/4 thick or maybe 1/2?, I forget what the power supply foam is but I think it's the thicker stuff) to replace it. I scrape off the old foam on the cover with a putty knife and clean to bare metal with goo-gone. Then I tape off the right size area and spray with adhesive spray. Remove the tape then press the air filter on. After it dries, button up the supply and reinstall it - you're good for another 20+ years :) I'd need to dig into the microcode test routines, but there MAY be other diagnostic selftests that could display before the battery backup check error (which is exactly as Glen states). 21MX M or E reference guide, which I can't find on bitsavers :) However, here's the scoop. In microcode there is a power up self test, and (separately) tests for FPP and SIS microcode. Let's deal with the self test microcode first. There's 3 self tests. Test 1 tests basic registers and functions, no memory. If this test fails, all display register bits, all indicator bits, and the over flow register will be on. Test 2 is a basic (read, doesn't catch many errors) memory test but ONLY the first 32kw of memory. This test is nondestructive. Errors usually show a parity error light, set all display registers and indicator bits, and clears the overflow register. A register is expected data, B register is bad data, M register is failing address. Note that the cpu front panel lights do NOT increment/count up like Glen mentioned during this test. Test 3 is a more comprehensive memory test, and it tests all memory installed not just 32kw. Each 32kw passing the test gets the display register incremented by one. Errors are reported the same as test 2, except the S register shows which 32kw block failed. Note that upon cold powerup, tests 1 and 3 are run automatically. That's it. No other tests. Note also, that kinda behind the scenes - anytime you press the IBL button to load a loader rom into ram, tests 1 and 2 are automatically run first. That's why it's labled IBL/TEST. You can also run tests 1 and 3 manually without powering on/off the machine. Set P register to 0, A register to 100000. Set the S register to whatever value you want memory filled with. Press PRESET. If you want to loop the diagnostic, set the LOCK/OPERATE switch under the front panel to LOCK, otherwise continue on. Press INSTR STEP and the diagnostic runs (and loops if lock switch set). If diag is looping, stop it by putting LOCK/OPERATE switch to OPERATE. To test the FPP, set 105004 in A register. Put 0 in P register and press PRESET. If overflow is on now, stop and go directly to the FPP installation/service manual. If overflow is not on, press INSTR STEP. A display of 102077 means all is well with FPP. To test the SIS, set 105477 in A register, 0 in P register. PRESET, then INSTR STEP. 102077 is good pass. FYI - these addresses/procedures aren't magic, they are just loading A register with an instruction from the user instruction group (used to call microcode). Then setting the P register to address 0 - the A register is addressible as memory address zero, and starting execution. Actually, I have this project all done eons ago... except for just one or two or three diagnostics aren't in absolute format! There's just 3 or less I think that are actually in relocatable format. Yes, I know how bizarre that is. But what it means is that the assembler listing for just those few diagnostics isn't particularly helpful. On all other diags, you can look at the halting address (or single step) and then look as the asm listing and see exactly what's going on. Not so if the program is relocatable. One of the listmembers took the diag source for these oddball relocatable ones and assembled it for me and produced a load map. This makes it fairly easy (with the extra step of adding the map's offset to the relocatable (from address zero) listing) to figure out where you are. So, this compilation of "the ultimate diagnostic cd reference" should be available soon. Jay