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Bill Baxter <bbaxter455123@msn.com>: Feb 05 10:28AM -0500 I have some Vivitar 283 flashes I used several years back in lower power mode for a special application (I swapped out the thyristor for a circuit that allowed 1/16th power). The flashes were controlled as slaves (using Wein peanuts) from my main camera, a Canon Rebel at the time. The flashes performed flawlessly for the few weeks that I needed them and then stored away.   After about 5 years and recently, I brought out the flashes to use now with my Pentax KX for macrophotography and thought they would be ideal still at 1/16th power. They started off working ok again as slaves with the peanuts, but have quickly become erratic and I don't know why. Not just one, but all of them after just a couple of days of use. What's generally happening is that they won't trigger from the main flash. I suspected the peanuts and swap them out, but they still won't respond. I used contact cleaner on the peanuts themselves, then carefully inserted into the 283's, but this didn't help. Also, even if I push the ready light button on the 283's, they won't fire. Sometimes the ready light is flashing, sometimes steady but doesn't seem to matter.   I can hear the whine of the flashes, mostly steady but in some cases pulsing as the light flashes. Nothing matters though as any/ all of the flashes won't flash. I've swapped out batteries for others, used the DC to AC adapter for the flashes, and mostly they won't respond or very erratically.   Any ideas what's going on? I do notice that if I short the hot shoe terminals, nothing is happening on any of the flashes. I can sometimes get them to fire if I keep bending them, but not always.   Any help for these 283's or time for something else? I'd hate to lose all 3 of them, but none of them seem to want to work properly.

"pfjw@aol.com" <pfjw@aol.com>: Feb 05 05:58AM -0800 Before I dive in blind, here are the symptoms:   This amp, which had worked nicely at our summer house (seasonal use) for 4 years died one evening - slowly going quiet over about 30 minutes (I was drowsing at the time and did not notice the problem until about the final 2 minutes). No heat, no smoke, no fan operation, no smell. I turned it off for an hour thinking a part may have overheated. When I turned it back on, it promptly blew the main PS fuse. This is a solid-state 100WPC amp built as with many things Revox like a tank. LCD display, capacitance controls, and so forth. It is also IR remote-capable.   I removed the unit from service and brought it home. Last night, after about a 18 months, I decided I would look it over. I replaced the fuse, and brought it up slowly on the variac. The first time, it drew about 45 watts, quiescent, no activity, no display, no pilot light. When I activated the on/off switch, the display went wonky - random pixels, random words, but no activity. No controls, including on/off responded after that point, but the draw went up to about 65 watts. I shut the unit down and held the on/off switch for 40 seconds (hey, it sometimes works with computers and other devices containing computers). This time, when I applied power and reached about 120V, the fan came on, the display showed other random stuff, but still no activity.   At this point, I decided that without direction, I would likely do more harm than good at random.   Thoughts? Suggestions? I am searching for the manual from HiFi engine, but I am also hoping that someone out there may have had some experience with these beasts.   Peter Wieck Melrose Park, PA

N_Cook <diverse@tcp.co.uk>: Feb 05 02:11PM > Thoughts? Suggestions? I am searching for the manual from HiFi engine, but I am also hoping that someone out there may have had some experience with these beasts.   > Peter Wieck > Melrose Park, PA   Cold DVM-D of the main devices show up any disparities?

"pfjw@aol.com" <pfjw@aol.com>: Feb 05 07:12AM -0800 On Friday, February 5, 2016 at 9:11:47 AM UTC-5, N_Cook wrote:   > Cold DVM-D of the main devices show up any disparities?   It will take me all of 30 minutes to get to the PS and its caps. Almost a complete dis assembly is required. Clearly you have not worked on Revox devices.... ;-)>.   I am looking for some direct experience with this unit before I dive in cold. But, as always and given my history, as with many here, I suspect the main filter caps.   This unit has a huge mother-board, with the remaining boards plugged in in layers. It is also liquid-cooled with a switching P/S.   http://www.revox-gebraucht.de/assets/Uploads/ReVox-B251-neu-Innen-+-Back-003.jpg   Peter Wieck Melrose Park, PA

"Mark Zacharias" <mark_zacharias@sbcglobal.net>: Feb 05 06:02AM -0600 > If it is a polarity problem, it could be in the outlet that the amp > is plugged into at home.   Just yesterday had a hum problem caused by the infamous "yellow glue turned brown"   The glue was apparently conductive enough to couple to a signal lead right at the edge of the goop.   Strangely, the hum was 60 hz instead of 120. Still haven't figured out that part.     Mark Z.

"pfjw@aol.com" <pfjw@aol.com>: Feb 05 06:01AM -0800 On Friday, February 5, 2016 at 7:02:41 AM UTC-5, Mark Zacharias wrote:   > Strangely, the hum was 60 hz instead of 120. Still haven't figured out that > part.   > Mark Z.   If the glue became conductive - then it would be due to a chemical salt within its composition. Many salts, by nature are diodes - so it would rectify only half the wave-form - 60 hz.   Just a random thought.   Peter Wieck Melrose Park, PA

mloo55 <mloo1955@gmail.com>: Feb 04 01:47PM -0800 At the time of turn con picture and audio are normal and aprox 15 secs later backligths do not ligth con so no picture. I checked voltages at the psu/inverter and all seems to be ok.ckd the inverter transformer no discrepancias notes and resoldering some suspictious points but the problemas continúes.could be any of the lamps and could you tell me the steps to reach them. Rgds   Mloo1955

thekmanrocks@gmail.com: Feb 04 06:08PM -0800 Sorry I don't know about anything internal on these TVs, but the reason your backlight is going is because it was left at maximum all its life. I'm probably the first to tell you that the backlight on a LCD or LED TV should be turned down to around the midpoint upon unpackaging and plugging it in.   It may appear relatively dim at first, but over time you'll grow to appreciate the more accurate picture.

mloo55 <mloo1955@gmail.com>: Feb 04 08:49PM -0800 On Thursday, February 4, 2016 at 4:48:01 PM UTC-5, mloo55 wrote: > At the time of turn con picture and audio are normal and aprox 15 secs later backligths do not ligth con so no picture. I checked voltages at the psu/inverter and all seems to be ok.ckd the inverter transformer no discrepancias notes and resoldering some suspictious points but the problemas continúes.could be any of the lamps and could you tell me the steps to reach them. > Rgds   > Mloo1955   well,thanks of for the hint. I will change the lamps.

Reinhard Zwirner <reinhard.zwirner@t-online.de>: Feb 04 06:38PM +0100 Cursitor Doom schrieb:   > "Current blasting"? It would have worked in this instance, but I've found > the problem with my good old trusty AVO which confirmed my previous > suspicions. ...   Would you be so kind and tell us what was wrong? Thanks in advance.   Best regardsw   Reinhard

Cursitor Doom <curd@notformail.com>: Feb 04 06:41PM On Thu, 04 Feb 2016 18:38:58 +0100, Reinhard Zwirner wrote:   > Would you be so kind and tell us what was wrong? Thanks in advance.   The problem was in the EHT converter section which creates 1600V from a 45V input. A BSW68 transistor in this section had fused low-resistance between C&E and was attempting to dissipate 340 watts all by itself - and it didn't even have a heatsink! :) The fact that its case had turned blue also hinted that it had been very hot. I couldn't see it on inspection initially as it was hidden by HV shielding. Now I just have to find an equivalent for it...

dansabrservices@yahoo.com: Feb 04 12:01PM -0800 On Thursday, February 4, 2016 at 1:44:26 PM UTC-5, Cursitor Doom wrote: > also hinted that it had been very hot. I couldn't see it on inspection > initially as it was hidden by HV shielding. > Now I just have to find an equivalent for it...   The BSW68 crosses to an ECG/NTE 190. It would seem that an MPSU04 would work as well.   A BSW-68 seems to cross to an ECG/NTE 198. Here a TIP-47 or TIP-48 would do.   Check further. It may be easier to use a sub.   Dan

Cursitor Doom <curd@notformail.com>: Feb 04 09:34PM On Thu, 04 Feb 2016 12:01:02 -0800, dansabrservices wrote:   > would do.   > Check further. It may be easier to use a sub.   > Dan   Thank you for those suggestions, Dan. I've got scores of TIP BJT variants lying around in my junk box. Many years ago I had a copy of Towers' Transistor Selector which listed a good range of equivalents for a vast range of devices. I guess these days there are web sites that perform the same function, but finding one worthy of trust that produces reliable results is another matter from what I've seen so far.

dansabrservices@yahoo.com: Feb 04 02:05PM -0800 For starters, I usually use the NTE cross reference. Since I have a rather large collection of NTE parts, I use these for experiments. I don't usually use NTE or ECG parts for a repair though. I try to use "real" parts. It does at least give me a quick try.   Dan

Cursitor Doom <curd@notformail.com>: Feb 04 11:22PM On Thu, 04 Feb 2016 14:05:40 -0800, dansabrservices wrote:   > rather large collection of NTE parts, I use these for experiments. I > don't usually use NTE or ECG parts for a repair though. I try to use > "real" parts. It does at least give me a quick try.   Good idea. Maybe I'll look into subbing that BJT for a power MOSFET. A lot of older gear uses BJTs in situations where a MOSFET would be de rigeur nowadays. This transistor functions as a chopper switching an inductive load in this circuit and it wouldn't require much tweaking to sub it for a better device, I reckon. In fact maybe that's why the original part failed or maybe its heatsink - if it ever had one - just fell off at some point, I can't say.

mloo55 <mloo1955@gmail.com>: Feb 04 12:24PM -0800 At the time of turn on the set picture and audio normal, anterior 10 sec no picture and backligths are Off, chkd voltajes and readings are normal, resoldered without good result. Any ideas about it. Rgds Mloo1955

Jeroni Paul <JERONI.PAUL@terra.es>: Feb 04 10:56AM -0800 Hello Miguel,   It`s been some time!   Maybe you could look at the video output from a scart or AV socket if it has one to see if something runs inside. Or input some signal in a scart with a set top box that enables the autoswitching signal and see if sound comes out the speakers.   Greetings

Jeroni Paul <JERONI.PAUL@terra.es>: Feb 04 10:57AM -0800 Hello Miguel,   It`s been some time!   Maybe you could look at the video output from a scart or AV socket if it has one to see if something runs inside. Or input some signal in a scart with a set top box that enables the autoswitching signal and see if sound comes out the speakers.   Greetings

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