- Hickok 440 Curve Tracer Repair Help - 7 Updates
- Lost two LCD monitors 12/2008 - 6 Updates
| Don Brown <edfredcorp@gmail.com>: Jun 25 06:54AM -0700 I have a Hickok 440 curve tracer that I am having difficulty troubleshooting, even though it is a relatively simple circuit. The base generator staircase is not stable, and will not stay in calibration. It looks like noise comes and goes and distorts it. I have replaced most of the semiconductors. The 15v power supply is a bit low at about 13.9v, though the regulator transistor and zeners have been replaced. I have the manual, schematic, parts and usual test equipment. Thank you, Don |
| John Robertson <spam@flippers.com>: Jun 25 08:00AM -0700 On 2019/06/25 6:54 a.m., Don Brown wrote: > I have the manual, schematic, parts and usual test equipment. > Thank you, > Don Have you replaced any and all electrolytic capacitors and verified that the resistors are on spec? Capacitors are bigger suspects than the semiconductors... John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| Don Brown <edfredcorp@gmail.com>: Jun 25 08:07AM -0700 On Tuesday, June 25, 2019 at 6:54:49 AM UTC-7, Don Brown wrote: > I have the manual, schematic, parts and usual test equipment. > Thank you, > Don I changed the two electrolytics in the 15v supply, and one polyester that is used in the base generator section (though it tested OK out of circuit). I did a quick run through on the resistors while in circuit, and they test within spec with nothing unusual. |
| Ralph Mowery <rmowery28146@earthlink.net>: Jun 25 11:08AM -0400 In article <o--dnbQEfIK0qo_AnZ2dnUU7-S2dnZ2d@giganews.com>, spam@flippers.com says... > Have you replaced any and all electrolytic capacitors and verified that > the resistors are on spec? > Capacitors are bigger suspects than the semiconductors... In older equipment it is always to suspect the electrolytic capacitors first. For older tube equipment the 1/2 and 1 watt carbon resistors often seem to go up in value and are the next thing after the capacitors I check for equipment that is sort of working,but not up to specifications. |
| Don Brown <edfredcorp@gmail.com>: Jun 25 08:09AM -0700 On Tuesday, June 25, 2019 at 6:54:49 AM UTC-7, Don Brown wrote: > I have the manual, schematic, parts and usual test equipment. > Thank you, > Don So the short answer is Yes. |
| John Robertson <spam@flippers.com>: Jun 25 08:50AM -0700 On 2019/06/25 8:09 a.m., Don Brown wrote: >> Thank you, >> Don > So the short answer is Yes. OK, caps and resistors all good. Then I'd scope the existing power supply to make sure it is clean & stable. If you have a good bench power supply see if using a different +15VDC source clears up the issue. John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| Don Brown <edfredcorp@gmail.com>: Jun 25 09:16AM -0700 On Tuesday, June 25, 2019 at 8:50:33 AM UTC-7, John Robertson wrote: > (604)872-5757 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out." I can do both. I did not think of an external power supply, will report back and post results. Thank you |
| bruce2bowser@gmail.com: Jun 24 10:26AM -0700 > > Computers should not be run in the rain, they need to be protected from > > the weather...unless specifically designed for outdoor all-weather use! > I dunno - were the OP to hold a 240 VAC power-supply for that computer between his legs in a driving rain, it may have a salubrious effect. 120 can be just as lethal as 240. (its the current, not the volts that's the problem in those accidents) |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jun 24 12:12PM -0700 > 120 can be just as lethal as 240. > (its the current, not the volts that's the problem in those accidents) But not nearly as fast or as certain. |
| Rheilly Phoull <rheilly@bigslong.com>: Jun 25 10:04AM +0800 >> 120 can be just as lethal as 240. >> (its the current, not the volts that's the problem in those accidents) > But not nearly as fast or as certain. And given the high resistance of the human bod I feel they are interactive, you cant have a current through high resistance with low voltage |
| Lucifer <LuciferMorningstar@bigpond.com>: Jun 25 07:53PM +1000 >> with an adaptor which means the surge wudda had to jump the induction coild >> (unlikely). I realy want to put som erational persectiv eon this. >You should consult Skybuck Flying, he is reasoning along the same lines. Af lakeys pacebar? |
| Lucifer <LuciferMorningstar@bigpond.com>: Jun 25 07:57PM +1000 On Mon, 24 Jun 2019 08:44:26 -0700, John Robertson <spam@flippers.com> wrote: >Computers should not be run in the rain, they need to be protected from >the weather...unless specifically designed for outdoor all-weather use! >John ;-#)# Her eallyn eedsa spellc hequera ndp roofr eading. |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jun 25 04:39AM -0700 On Monday, June 24, 2019 at 10:04:12 PM UTC-4, Rheilly Phoull wrote: > And given the high resistance of the human bod I feel they are > interactive, you cant have a current through high resistance with low > voltage The (healthy adult) human body is, effectively, a 10,000 ohm, 1/4-watt resistor. Anything that will put more than 1/4 watt through 10,000 ohms will cause damage. Peter Wieck Melrose Park, PA |
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