- Hickok 440 Curve Tracer Repair Help - 9 Updates
| Jeff Urban <jurb6006@gmail.com>: Jun 26 12:59PM -0700 You can't attach things here. Bama probably has it but I can't confirm it right now because of this wonky MODEM that is going back to SBC with stab wounds, three bullet holes and half burned by a Bernzomatic torch. I am seriously about to jump ship but the only other thing I can get here is Hughesnet and in this area since there is a temporary rain forest to the south every year it is going to drop when it rains south of here just like the Dish TV thing. But you probably got it online, just throw up a link. I suppose I don't have to tell you to scrutinize every small signal PNP in there right ? Nice thing is they all work the same. You should be able to put a low value resistor on the base drive and derive current that way. the noise and whatever have to be there. You can leave that on one channel of the scope and just start going backwards with the other. Unless you already have, if you are sure it is at the beginning of the "chain". Nice to have it localised of course but when things get old they get weird failure modes. I have seen PC boards that worked for more than a decade and then came to me and looking for a bad connection on the board bending things a huge piece of solder simply came off the copper. It wasn't clean enough when they wave soldered it but it took all that time to manifest itself. I think on this unit you are probably down to the small caps. some of them like to be a piece of wire sometimes. More later, I am going to go shoot the MODEM. Don't worry I got another one. |
| Fox's Mercantile <jdangus@att.net>: Jun 26 03:51PM -0500 On 6/26/19 2:59 PM, Jeff Urban wrote: > Bama probably has it but I can't confirm it right now They don't. <http://bama.edebris.com/manuals/hickok/> -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| Don Brown <edfredcorp@gmail.com>: Jun 26 01:53PM -0700 On Wednesday, June 26, 2019 at 1:51:20 PM UTC-7, Fox's Mercantile wrote: > Jeff-1.0 > WA6FWi > http:foxsmercantile.com I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. |
| Don Brown <edfredcorp@gmail.com>: Jun 26 03:00PM -0700 On Wednesday, June 26, 2019 at 1:53:53 PM UTC-7, Don Brown wrote: > > WA6FWi > > http:foxsmercantile.com > I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. Here is a photo gallery that I created with the schematic and circuit description: http://www.edfredcorp.com/Hickok/httphotos/index.html |
| Don Brown <edfredcorp@gmail.com>: Jun 26 03:40PM -0700 On Wednesday, June 26, 2019 at 1:53:53 PM UTC-7, Don Brown wrote: > > WA6FWi > > http:foxsmercantile.com > I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. Here is a photo gallery that I created with the schematic and circuit description: http://www.edfredcorp.com/Hickok/httphotos/index.html And an enlarged schematic link: http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickock%20440%20Schematic.jpg |
| Don Brown <edfredcorp@gmail.com>: Jun 26 03:42PM -0700 On Wednesday, June 26, 2019 at 1:53:53 PM UTC-7, Don Brown wrote: > > WA6FWi > > http:foxsmercantile.com > I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. Here is a photo gallery that I created with the schematic and circuit description: http://www.edfredcorp.com/Hickok/httphotos/index.html And here is a link for a high resolution schematic: http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickock%20440%20Schematic.jpg |
| Don Brown <edfredcorp@gmail.com>: Jun 26 04:17PM -0700 On Wednesday, June 26, 2019 at 3:42:36 PM UTC-7, Don Brown wrote: > > I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. > Here is a photo gallery that I created with the schematic and circuit description: http://www.edfredcorp.com/Hickok/httphotos/index.html > And here is a link for a high resolution schematic: http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickock%20440%20Schematic.jpg By temporarily reducing the resistance of R22 & R23 in the 15+ & 15- I was able to bring up voltages to exactly 15v.That does heat up the zeners, which I upgraded from 1/2W to 15v 1W. No change on stability issue. |
| John Robertson <spam@flippers.com>: Jun 26 08:06PM -0700 On 2019/06/26 3:42 p.m., Don Brown wrote: >> I looked everywhere for it and ended up buying the hard copy. So I need to scan it and link it. > Here is a photo gallery that I created with the schematic and circuit description: http://www.edfredcorp.com/Hickok/httphotos/index.html > And here is a link for a high resolution schematic: http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickock%20440%20Schematic.jpg Hi Dan, The Heathkit IT-1121 curve tracer is somewhat similar to your schematic. Have you read that manual? Pretty sure you can download it from www.tech-systems-labs.com - use web.archive.org and look in 2007 archives... 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 26 09:10PM -0700 On Wednesday, June 26, 2019 at 8:06:47 PM UTC-7, John Robertson wrote: > (604)872-5757 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out." I will review the Heathkit manual. I am new to curve tracers and have several manuals to study and plenty to learn. My problem is intermittent. Cannot find what causes it yet. It does not change with length of time on (heat), case open or closed, switch movements or settings, tapping components. Maybe she is like me, getting old and not consistently useful. I took some photos of when it is at it's best: Here is a sample curve trace - http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickok%20440%20Curve%20Test%20Scope%20Screenshot%20Working.jpg Here is the calibration screen, fairly normal I think with two steps per division as expected - http://www.edfredcorp.com/Hickok/httphotos/Hickok_20440_20Schematic_20_26_20Circuit_20Description/Hickok%20440%20Calibration%20Scope%20Screenshot%20Working.jpg |
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