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simondavidbond@gmail.com: Jul 08 09:23AM -0700 Hi guys, Did you ever get your Chase radio working again? Simon

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 07 07:40PM +0100 "N_Cook" <diverse@tcp.co.uk> wrote in message news:ojnaei$a8k$1@dont-email.me... >> is....................   >> Thanks for any help.   > 1 second fire-up, followed by scanning with IR thermometer?   Putting some components back in the wrong place in a SMPSU doesn't usually leave time to switch on a IR thermometer.

Don Kuenz <g@crcomp.net>: Jul 07 06:50PM > handy.   > Or I could just fire it up and see how loud the bang is....................   > Thanks for any help.   Have you tried http://www.badcaps.net ?   Thank you,   -- Don Kuenz, KB7RPU

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 07 09:49PM +0100 "Don Kuenz" <g@crcomp.net> wrote in message news:20170707c@crcomp.net... >> is....................   >> Thanks for any help.   > Have you tried http://www.badcaps.net ?   That isn't going to tell me which capacitors I put in the wrong holes.

Don Kuenz <g@crcomp.net>: Jul 08 12:58AM >>> Thanks for any help.   >> Have you tried http://www.badcaps.net ?   > That isn't going to tell me which capacitors I put in the wrong holes.   The guys in the badcaps.net Power Supply Design and Troubleshooting forum might surprise you. They're the most passionate group of PSU enthusiasts on the Inet AFAIK. They love to reverse engineer undocumented PSUs. They may even have the service manual that you seek or a pertinent schematic. The only downside is that you need to sign up to access the forum.   Thank you,   -- Don Kuenz, KB7RPU

mhooker32@gmail.com: Jul 07 10:01AM -0700 On Friday, July 7, 2017 at 12:09:33 PM UTC-4, rickman wrote: > What does the pump drive signal on pin 7 look like?   > --   > Rick C   pin 3 of 7833 is 25.65 v. pins 2 and 15 are opposite polarity. pump drive signal is a .5 volts upside down sawtooth.   i appreciate the time taken here. i could just send this out, but i think i am close, just not there.

jurb6006@gmail.com: Jul 07 10:24AM -0700 Ramp generator, probably at whatever that unit's equivalent of a jungle IC is. An IC is only as good as what is fed into it. Yoke problems are rare and thus unlikely.   You need a proper sawtooth wave driving that IC or it will not put out what you want. It is that simple. So go backwards and find that ramp generator. If you cannot find it, put up a link to the print and I will. If you do, please use something that an older PC can use.

rickman <gnuarm@gmail.com>: Jul 07 01:36PM -0400 >> Rick C   > pin 3 of 7833 is 25.65 v. pins 2 and 15 are opposite polarity. pump drive signal is a .5 volts upside down sawtooth.   > i appreciate the time taken here. i could just send this out, but i think i am close, just not there.   If pin 7 pump drive signal is only half a volt, I would say your problem is there. Pin 3 should clearly be more than 25 volts and it is this signal that drives that voltage. Is pin 3 at all steady or is it also a waveform? You should measure the voltage with the scope, not the meter. They don't use a smoothing cap so I guess the voltage will pulse with the drive. During retrace you don't need a high voltage on pin 3. Retrace is when the voltage goes below 24 volts and the diode is forward biased to charge up the cap again.   I think you said you already replaced the LA7833, so there are only two other parts. When you say pin 7 is "upside down", do you mean it is normally high and drops low or it is going negative? I would expect it to be near 24 volts during the picture time and drops low during retrace as the cap charges. I guess the question is how does the waveform on pin 3 look? I would expect it mostly near 48 volts dropping slightly below 24 volts during retrace. Pin 7 should definitely have a significant pulse voltage on it.   --   Rick C

John Robertson <spam@flippers.com>: Jul 07 11:39AM -0700 >> Rick C   > pin 3 of 7833 is 25.65 v. pins 2 and 15 are opposite polarity. pump drive signal is a .5 volts upside down sawtooth.   > i appreciate the time taken here. i could just send this out, but i think i am close, just not there.   Afraid we don't have one on the service bench otherwise I would be happy to send you waveform images. One of those monitors is in my storage area I'm pretty sure, but...     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."

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 07 07:42PM +0100 "John Robertson" <spam@flippers.com> wrote in message news:3rudnUQ-koXXLMPEnZ2dnUU7-RPNnZ2d@giganews.com... > Anatek (we carry it on Flippers), but you would be better off with an > inductance meter - split the vertical windings and each side should be > identical.   I tried the DSE ringer on pretty much anything laying around - it doesn't like very low inductances.   Scan yokes should be fine.

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 07 07:44PM +0100 "John Robertson" <spam@flippers.com> wrote in message news:3rudnUc-koUQLMPEnZ2dnUU7-ROdnZ2d@giganews.com...   >> There might be a flyback diode lurking nearby - it could've gone leaky.   > Flyback diode won't affect the vertical deflection. You will lose the HOT > though if that diode is open. Nowadays they are part of the HOT though.   The one in the vertical output section can and does.

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 07 09:52PM +0100 "John Robertson" <spam@flippers.com> wrote in message news:ComdnW2tcfL-SMLEnZ2dnUU7-L3NnZ2d@giganews.com...   > Afraid we don't have one on the service bench otherwise I would be happy > to send you waveform images. One of those monitors is in my storage area > I'm pretty sure, but...   Pretty sure you can wire up an adaptor to run VGA off a CGA output - for some strange reason, many VGA monitors aren't backward compatible with EGA.

John Robertson <spam@flippers.com>: Jul 07 03:25PM -0700 On 2017/07/07 1:52 PM, Ian Field wrote: >> storage area I'm pretty sure, but...   > Pretty sure you can wire up an adaptor to run VGA off a CGA output - for > some strange reason, many VGA monitors aren't backward compatible with EGA.   There are CGA -> VGA adapters on eBay all the time. Cheap. Most work, some don't so do some research first.   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."

mhooker32@gmail.com: Jul 07 03:34PM -0700 > Ramp generator, probably at whatever that unit's equivalent of a jungle IC is. An IC is only as good as what is fed into it. Yoke problems are rare and thus unlikely.   > You need a proper sawtooth wave driving that IC or it will not put out what you want. It is that simple. So go backwards and find that ramp generator. If you cannot find it, put up a link to the print and I will. If you do, please use something that an older PC can use.   https://na.suzohapp.com/pdf/service_pdfs/support/visionpro/49-1329-vp2_schematic.pdf

amdx <nojunk@knology.net>: Jul 07 12:26PM -0500 On 7/7/2017 8:01 AM, John-Del wrote:   > Yes, it was indeed poor troubleshooting on the buyer's end and now it's aggravation for you. Samsung LED failures are epidemic, and the repair shop should have known this. Most shops built their own LED testing tools years ago, but now anyone can buy a tester for LED strips that will light even give a voltage readout of the run voltage of any given strip at the tester's preset current limit, and do so without disassembling the display.   > It's possible that the buyer made the return request in the hopes you would credit back the money and tell them to keep the board. It wouldn't surprise me if you don't hear from them again.   > Too bad you also didn't remove the LED strips from the carcass before scrapping it. These bring good money and are in high demand.   This was a CFL unit, I didn't want to mess with those. Ebay requested the purchaser to return the item by 7-06-17, it didn't happen. You may be right, in saying he wanted me to credit back the money and tell them to keep the board. I didn't :-) I think it is common for shops to replace pcb's on flat screens. I worked at a electronics shop 25+ yrs ago repairing VCRs. It was all component level on the VCR's but I did note the TV tech replaced a lot of boards. I sometimes helped him on tough dogs, and he was always impressed that I'd fix a TV at component level, he had spent hours on, that may tell you something about that TV tech.

John-Del <ohger1s@gmail.com>: Jul 07 01:18PM -0700 On Friday, July 7, 2017 at 1:26:48 PM UTC-4, amdx wrote:   > > It's possible that the buyer made the return request in the hopes you would credit back the money and tell them to keep the board. It wouldn't surprise me if you don't hear from them again.   > > Too bad you also didn't remove the LED strips from the carcass before scrapping it. These bring good money and are in high demand.   > This was a CFL unit, I didn't want to mess with those.   Ah.. I used to save CCFL tubes and I still have an assortment. Too much trouble to ship safely although many try.   In any case, the TV shop still screwed up. CCFL tubes are easier to check than LEDs. Put a scope probe *in proximity* to the secondary of each CCFL output transformer and watch the waveform. It's important to put the probe in the exact same spot for each as the waveform's amplitude changes significantly with a small physical placement of the probe. A waveform that is much higher and distorted than the rest indicate an open or very lazy tube, or a corroded connection on the tube cap. In any case, playing musical chairs with the inverter transformers to see if the abnormal waveform stays with the suspected tube or follows the transformer quickly identifies this as either a tube problem or inverter problem.     > I worked at a electronics shop 25+ yrs ago repairing VCRs. It was all > component level on the VCR's but I did note the TV tech replaced a lot > of boards.   If you want to make money and do it quickly, you can't be changing boards unless they're particularly cheap. Component level is all we ever did but the problem these days is that even companies like Samsung are not providing full schematics. This means I spend time looking at datasheets and using the "representative" circuit as a guideline for doing component level repair. Fortunately, parts that manufacturers don't sell us can usually be sourced from China. I never order one, I always order 10.

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