Hewlett Packard 10548A Diagnostic Service Kit

After spend­ing many hours work­ing on my Hewlett Packard 5300 series mea­sur­ing sys­tems, I decid­ed to remake my own ver­sion of the HP 10548A diag­nos­tic ser­vice kit.

New HP 5300 Diagnostic Interface test card set­up for test #3

The HP 5300 series mea­sur­ing sys­tem is not an easy sys­tem to trou­bleshoot and work on. Typically there are two mod­ules with a 50 pin con­nec­tor between them. The upper main­frame dis­play mod­ule includes the pow­er sup­ply, 10 MHz oscil­la­tor, counter, time base divider, con­trol cir­cuits, and dig­i­tal dis­play.
The low­er plug-on mod­ule con­tains cir­cuit­ry for sig­nal input, atten­u­at­ing, ampli­fi­ca­tion, mode selec­tion con­trol, and annun­ci­a­tor con­trol.
When con­nect­ed togeth­er, only one side of each mod­ule’s cir­cuit board is eas­i­ly acces­si­ble for trou­bleshoot­ing. Generally nei­ther mod­ule will func­tion with­out being con­nect­ed to it’s oth­er halve.
The HP diag­nos­tic ser­vice kit allows a tech­ni­cian to ser­vice the 5300 series main­frame dis­play mod­ule with­out a plug-on mod­ule attached. It also pro­vides easy access to many of the con­trol and data sig­nals on the module.

Based on the HP 5300B ser­vice man­u­al, I designed a cir­cuit board based on the infor­ma­tion found in tables 5–2 thru 5–4. I decid­ed not to dupli­cate the orig­i­nal diag­nos­tic ser­vice kit, and to build a com­pact board that uses jumpers and a switch to accom­plish the con­nec­tions pro­vid­ed by the orig­i­nal four test cards.
I had already made a sim­i­lar type of board for the HP 3470 series dis­play mod­ules. Instead of tur­ret ter­mi­nals this board uses sock­ets com­pat­i­ble with stan­dard bread­board jumpers to make up the required con­nec­tions for each of the tests.

Shortly after send­ing off the board design to be pro­duced by OSH Park, I came across an Ebay list­ing for an orig­i­nal HP diag­nos­tic inter­face con­nec­tor and two test cards. They are now mine!

HP 05300–60004 Diagnostic Interface Connector, angle view

The inter­face con­nec­tor 05300–60004 con­verts from the Centronics style 50 pin con­nec­tor found on the 5300 series main­frame dis­play mod­ule and a 44 pin female sock­et for the diag­nos­tic test cards.

HP 5300 series diag­nos­tic inter­face card front
HP 5300 series diag­nos­tic inter­face card back

Each diag­nos­tic card has four board edge con­nec­tors for each of the four tests per card.
Diagnostic card A checks the dis­play cir­cuit­ry using tests 1–4. Diagnostic card B checks the inputs and out­puts of the var­i­ous modes of oper­a­tion, the annun­ci­a­tors and dec­i­mal points using tests 5–8. Diagnostic card C and D tests 9–16 test the time base cir­cuit­ry and decade counter.

Hewlett Packard 5300 series diag­nos­tic card B front
Hewlett Packard 5300 series diag­nos­tic card B back

Unfortunately I was not able to find test cards A and C, but it was inter­est­ing to see how HP imple­ment­ed the card jumpers on the two cards I received.
On my diag­nos­tic card I decid­ed to use a rotary switch for the annun­ci­a­tor and dec­i­mal point indi­ca­tor test, where on test card B test 8, HP decid­ed to use jumpers for test­ing those functions.

Hewlett Packard 5300 series diag­nos­tic card D front
Hewlett Packard 5300 series diag­nos­tic card D back

On my diag­nos­tic card I added tur­ret ter­mi­nals for ground, reset, and the five pow­er sup­ply volt­ages avail­able on the con­nec­tor. The 3.5 volt sup­ply does­n’t con­nect to the con­nec­tor as it is only used for pow­er­ing the front pan­el dis­play, and must be checked from the test point on the main­frame module.

HP 5300 series test card bare boards from OSH Park
Assembled HP 5300 series Display Module Test Card rev. A

I print­ed the test jumper posi­tions on the back of the card based on the infor­ma­tion pro­vid­ed in the HP 5300B ser­vice man­u­al. For some rea­son test 5 isn’t includ­ed in the 5300B man­u­al, but is includ­ed in the 5300A man­u­al. In the EagleCAD files for revi­sion B, I added an extra ground (4–7) to accom­mo­date test #5’s need for anoth­er ground jumper.
I also added an onboard pow­er switch for anoth­er method of switch­ing pow­er along with the mod­ules rotary pow­er switch. Both switch­es must be enabled to pow­er up the module.

HP 5300 series test card, jumper set­up for test 7

So far the new test card has worked well and has been used on a HP 5300A and 5300B for troubleshooting.

Troubleshooting a HP 5300A main­frame using test #4

EagleCAD V7.7 schemat­ic and board Rev. B ZIP file
Bill Of Materials BOM for Test Card Revision B
OSH Park shared project page for 5300 Test Card Rev B

Leave a Reply

Your email address will not be published. Required fields are marked *