| Electronics > Repair |
| Series defect on agilent 167xx boards? |
| << < (44/50) > >> |
| John_ITIC:
--- Quote ---That would cause backplane pins 2, 20, 22, 26, 36 to short together from one cable, and pins 38, 56, 58, 62, 72 to short together from the other cable. --- End quote --- --- Quote ---I've done a little poking at the backplane about a year ago, and was able to take some reasonable guesses at some of the signals by direct measurements and looking at a broken 16531A scope module. The 16531A is thru-hole, so it was a lot easier to see where various traces were going. Here's what I have so far. Any pin where I didn't have a good guess is not listed. I would think shorting the -5.2V supply did the most damage, since it's also responsible for supplying the power-hungry ECL on the modules. --- End quote --- Thank you both. I will eventually make an attempt to fix the shorted 16754A. But first, Ill take a stab at my three other 16754A boards that all fail the RC comp and Tap delay calibration. I have one good 16754A board that I want to compare with live on the bench. So here's a summary of your information: Pin(s) Signal ------ ----------------------- 1-5 +5V 6-8 +3.3V 9-10 +12V 11-12 -12V 13-14 GND 15 D7 bi-directional (D7:D0 based on 16531A DAC) 16 D6 bi-directional 17 D5 bi-directional 18 D4 bi-directional 19 D3 bi-directional 20 D2 bi-directional <= shorted to +5V (pin 2) 21 D1 bi-directional 22 D0 bi-directional <= shorted to +5V (pin 2) 23-24 GND 26 from backplane <= shorted to +5V (pin 2) 27 from backplane 28 from backplane, A1 on DAC 29 from backplane, A0 on DAC 30 from backplane, 138 both decode select C 31 from backplane, 138 both decode select B 32 from backplane, 138 both decode select A 33-34 GND 35 from backplane, R/nW, select which 138 decoder 36 UNKNOWN <= shorted to +5V (pin 2) 37 from backplane, 134 both G2A not enable 38 UNKNOWN <= shorted to -5.2V (pin 72) 43-44 GND 53-54 GND 55 100MHz system clock 56 100MHz system not clock <= shorted to -5.2V (pin 72) 58 UNKNOWN <= shorted to -5.2V (pin 72) 62 from backplane, 138 decode G1 <= shorted to -5.2V (pin 72) 63-67 -3.3V 68-72 -5.2V I also found another two 16754A boards sitting in a stored away 16702A so I will need to fix the rail corrosion on those too. This will all take a lot of time... Thanks, /John. |
| dorkshoei:
--- Quote from: John_ITIC on March 05, 2024, 02:35:32 am --- --- Quote ---Thanks for the order though I hate giving 13% to those eBay bloodsuckers. I have several other boards from the same 16700b for sale. All working. PM me here. --- End quote --- PM sent. --- End quote --- If anyone else wants parts off the 16700B that I put onto eBay (that John_ITIC bought the interface pcb from). PM me. I'll happily offer 10% discount for direct sales. |
| John_ITIC:
--- Quote from: dorkshoei on March 05, 2024, 02:52:57 am ---John_ITIC bought the interface pcb --- End quote --- I can report that the replacement main interface board made my burnt out 16700B work again. Thank you! I also have made another interesting observation: Having moved 16754A boards between various systems (16700B and 16702A), I noticed that some 16754A boards fail more pv self tests in some 16700 systems than in other 16700 systems. I also noticed that the some 16754A boards could not handle even 17" long extension cables without starting to fail the dataBusTest, hwMemoryCellTest and some others. However, other 16754A boards worked fine with 40" extension cables. I have not managed to get any 16754A board pass self tests with 52" extension cables, however. I'm suspecting not correct power integrity on some boards / 16700 combinations can cause memory test failures. The search goes on. /John. |
| dorkshoei:
--- Quote from: John_ITIC on March 09, 2024, 03:31:50 am --- --- Quote from: dorkshoei on March 05, 2024, 02:52:57 am ---John_ITIC bought the interface pcb --- End quote --- I can report that the replacement main interface board made my burnt out 16700B work again. Thank you! --- End quote --- Great. Please post if you get the old board repaired |
| MarkL:
FWIW, I've been using DogP's extenders with a 16" cable without any issues. So far I've only used it with a 16752A card. I added some connectors in the middle of the extender cables to probe bus power and signals more easily. The red marks are positive supplies, blue are negative, and black are grounds. Unused wires in the ribbon are covered with red tape. The ribbon is also slit in one area, with the wires being grouped into each supply rail. This allows me to measure the current on each rail by passing the group through a current probe. Being paranoid, the bus numbering is everywhere. And given the number of fans in the chassis, I felt a fan blowing over the heatsinks when the card away from home would make it feel less home sick. |
| Navigation |
| Message Index |
| Next page |
| Previous page |