Working Through The HP 3563a CSA

[lancelotburt]

I'm working my way through the start-up sequence to get this HP 3563A going.  As it arrived - powers on, no display, no keyboard response.  The power supply checked out.  Battery dead so I replaced that.  After reseating all the A2 processor board chips and jumpers, and resetting the battery jumper (non-volatile ram), it makes it through the start-up LED ROM/RAM sequence without errors, the keyboard is responsive, but the display is still dark.  The A38 Memory board has a single red LED on it that lights as the A2 processor is 1/2 way through the High Level Power-up Tests.  I have scoured both service manuals and find no info on the A38 LED and no schematic for the A38 board. 

Any 3563A experts out there? Red LED good or bad?

[lancelotburt]

Found it in the 3562a manual I'm thinking, even though the boards are somewhat differently layed out on the 62a.  The Ram board has a single LED on the top edge of the card that indicates RFD on the system bus.  It is not used for board diagnostics.

On to the CRT PS check.

[lancelotburt]

So, the 1A fuse on the CRT Low Voltage, -15v supply is being blown.  Looks like the culprit is on the A81 Analog X, Y, Z board.  The negative voltage regulator on that board has been replaced before, though the 100uf/25v electrolytic right before it hasn't, and has an ESR of 5.8 ohms.

[lancelotburt]

Uhh.  Misread that.  ESR is .58. 

A bit further into the -15v, the - shorted supply voltage for the D/A converters, I found the culprit, a little, shorted tantalum bugger.  Have to replace all of those.

[lancelotburt]

I ended up getting another display unit with a bad tube and swapped out the A81 XYZ and the digital interface board.  Now everything works and my original tube (3019A...) is very good.  Happy.

Now Self Tests.  FFT ROM and FFT Global Interface fail.  I forgot to reset the profile.  See if that helps...

[lancelotburt]

Replaced FFT board.  Everything is working.  Nice old box!