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| HP 5335A Timer / Counter - Anything i should know? |
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| orin:
--- Quote from: 1980s_john on March 27, 2015, 11:53:41 pm --- --- Quote from: orin on March 04, 2015, 06:03:16 pm ---If you have the DC fan, it's likely that the contacts on the relay socket have opened up. See the service note in my post above. The relay socket is a 27E213, Digikey part number PB806-ND. If it is the relay socket and you do the modification in the service note, you probably don't need a new relay; I'm still using my original relay. Anyone with a 5335A should make sure that this modification is done and switch to a DC fan. The 5V supply relay socket contacts get hot, fatigue and eventually, when they cool down, don't make contact with the relay any more. --- End quote --- Thanks, my relay seems to be OK. However removing it shows a black heat mark on the socket, presumably where the 5V passes through. Thanks for the service note, I must give it a go. The HP part for the relay is 0490-1172. Printed on the side is the code R10A-E1-X6-V430, and a date code 7923. ebay shows loads of R10-E1-X6-V430, is the R10 2A relay and the R10A 5A then? Regards, John --- End quote --- Sorry, R10-E1-X6-V430 won't work. It is a 6PDT relay and wouldn't even fit the socket (18 contact pins) whereas the original R10A is a 6PST relay (12 contact pins). The V23154-D0721-B112 is a 6PST 2A relay that might work - the contact arrangement appears to be correct. Onlinecomponents.com have a couple available, but $50 each. You'd definitely need the service note modification as I measured the current on the 5V supply at up to 2.2A. Orin. |
| Wim13:
--- Quote from: 1980s_john on March 27, 2015, 11:35:44 pm --- I finally got around to working on my 5335A, the service manual is a must have. The input board is the 'A3 Amplifier Buffer assembly (05335-60003)', I replaced the big blue tant caps (22uF) with new 35V parts. It now powers up and the front panel / processor / display appear to work, but it is not working as the PSU voltages are still not right. I get: -15V output = +0.7V +5V = 5.07V +10V=10.0V +15V=15.7V -5.2V=+0.6V +3V=3.0V So problems with the -15V and -5.2V rails, which appear to be independent. Any tips please? Regards, John --- End quote --- Replace the -15V regulator by a 7915, the -5 volts is depended on the -15V. because of the op-amp that is in line with the -5 V |
| 1980s_john:
--- Quote from: Wim13 on March 29, 2015, 01:14:01 pm ---Replace the -15V regulator by a 7915, the -5 volts is depended on the -15V. because of the op-amp that is in line with the -5 V. --- End quote --- Thanks, I've started removing / unplugging boards to get to the A1 Power Supply board. With A3/A6/A9 removed, the unit now brings up -15V and -5V but only intermittently :(. It may be a failing -15V regulator, I see someone has been there before me and a 7915 is already fitted. I will try and measure the max. current available on -15V and -5V with no boards plugged in, then replace the 7915 and measure max current again. I will replace the fan with a 24V one and rewire the 5V at the same time (currently have a 115V fan fitted and working fine). No more progress for a few weeks, I wish everyone a Happy Easter! Regards, John |
| Vgkid:
Does the fan blow into the unit, or out? Also is it safe to go with a 32cfm fan(26db), or go with the updated 36cfm(29db) fan. Mines starting to get loud. |
| PE1RKI:
mine blows out. i dont mind the noise unless the fan is breaking down or rattling, then i will replace it with a simular one. |
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