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Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Jan 17 06:01AM +1100 On 15/01/2016 1:52 PM, John Heath wrote: > in a music store as he will have a tube tester and has been there > done that many times and will know how to match output tubes and > change coupling condensers if necessary.   **Thanks for the tips, but the job was completed a couple of days ago. A few points:   * I have a valve tester (AVO VCM163). * The initial fault (AFAICT) was due to the owner transporting the foot pedal inside the enclosure. At some time, the foot pedal made contact with the nipple on one EL84, thus allowing the ingress of air. Amp was switched on and two other valves failed soon after. * I am quite comfortable servicing valve amps, but, due to the output stage arrangement, I was curious about the importance of matched output valves. * Control grid Voltages were within spec, as were all other Voltages (though plates were a little higher than the schematic indicated, due to higher local mains supply (240VAC). * The local Peavey agent supplied a schematic and board layout. * The screen supply had also failed.   -- Trevor Wilson www.rageaudio.com.au   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

John Heath <heathjohn2@gmail.com>: Jan 16 12:02PM -0800 On Saturday, January 16, 2016 at 2:05:19 PM UTC-5, Trevor Wilson wrote:   > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus   I do not see feedback from output tubes to split phase tube as can be seen on the diagram. With solid state amps there is feedback from output to input so matching gain is a non issue. However in your case of a tube amp without the benefit of feedback to correct for this leaves you vulnerable to the gain of the output tubes. Then again soft distortion from the limits of tube amplifiers is the charm of having tube amps and the reason they are still sold today. Play and enjoy as perfection is not the goal of music.   Just check now and then that the output plated are not glowing red hot. If this is the case then coupling condensers C32 and C35 are suspect and could smoke those expensive output tubes. Do not mean to be pessimistic or rain on your parade but when you are in the service business all electronic equipment is junk as I only see it when it is broken not working. Your own experience in service will confirm this. Eye ball the tubes now and then to make sure the plates are not red hot in the same way you check the oil now and then in your car. Speaking of this I need to get off the net and buy some antifreeze :).

Phil Allison <pallison49@gmail.com>: Jan 16 07:18PM -0800 John Heath wrote:     > I do not see feedback from output tubes to split phase tube as can be seen on the diagram.   ** Feedback comes from the 8ohm tap on the output transformer to the cathode of V3A. The phase splitter cannot accept feedback since it uses the "concertina" circuit rather than the more common cathode coupled pair.   Tube matching is normally refers to nominally identical tubes that show the same plate current under class A conditions. For pentode and beam power tubes, actual plate and screen voltages are critical so the best test conditions are those found in the amp itself.     ... Phil

Phil Allison <pallison49@gmail.com>: Jan 16 08:04PM -0800 Trevor Wilson wrote:   > * I have a valve tester (AVO VCM163).   ** The VCM163 ( Valve Characteristic Meter) is oddball among valve testers, uses only AC voltages for ALL supplies - plates, screens and grids !!   http://www.radiomuseum.org/forum/tube_tester_avo_vcm_163_measurement_principle.html   Expensive too, working examples go on Ebay for up to $3000.     > pedal inside the enclosure. At some time, the foot pedal made contact > with the nipple on one EL84, thus allowing the ingress of air. Amp was > switched on and two other valves failed soon after.   ** Valves need a good vacuum in order to work. When air gets in, valves stop working immediately and a broken nipple lets air in FAST.   You previously said three 3 valves had let air in ??   BTW most versions of the Classic30 leave the valves fully exposed:   http://profile.ultimate-guitar.com/profile_mojo_data/3/3/6/5/336564/pics/_c32086_image_0.jpg   Later versions have a full, perforated steel cover over all the valves.     .... Phil

John Heath <heathjohn2@gmail.com>: Jan 16 10:09PM -0800 On Saturday, January 16, 2016 at 10:18:09 PM UTC-5, Phil Allison wrote:   > ** Feedback comes from the 8ohm tap on the output transformer to the cathode of V3A. The phase splitter cannot accept feedback since it uses the "concertina" circuit rather than the more common cathode coupled pair.   > Tube matching is normally refers to nominally identical tubes that show the same plate current under class A conditions. For pentode and beam power tubes, actual plate and screen voltages are critical so the best test conditions are those found in the amp itself.   > ... Phil   Yes , now I see it. It is marked with a big sign saying FEEDBACK --> , ha. So who cares about matching tubes if it has feedback. The feedback should compensate for that yes / no ? As long as the output idling current is in a reasonable range and not increasing over time it should be okay. There is an obligation in service to look after the customer's best interest. Does he need German imported tubes with color coded matched specification or will a china cheap knockoff do just as well. I suspect the latter is in the costumer's interest.   And I would add that the rumor that China products are of less quality is just sour grapes from an industry that can not compete. 90 percent of all desktop , laptop , flat TVs and cell phones come from China. These are not the easy but the hardest electronic products to make and they are all coming from the shores of China. The winds of change are in the air. I can see I am rambling off topic. Why is it when we get older there is a need to talk all the time? It is as if life as filled the brain with stuff so you need to talk to vent some of it off.

Jeff Liebermann <jeffl@cruzio.com>: Jan 16 10:31AM -0800 On Fri, 15 Jan 2016 11:15:52 -0800, Jeff Liebermann <jeffl@cruzio.com> wrote:   >harder. Digging: ><http://www.siliconeforbuilding.com/pdf/structuralglazing/Data_Sheet_SSG4000_UltraGlaze.pdf> >Argh... only 39.   One of my customers, who customizes automobiles, recommended this stuff: <https://www.freemansupply.com/products/liquid-tooling-materials/mold-making-silicone-rubber/bluestar-addition-cure-silicone-rubber/v-340-mold-making-silicone-rubber-low-viscosity> <http://www.miapoxy.com/p-124-bluestar-v-340-silicone-rubber.aspx> Note the 400% elongation before tearing. Ideal would be 45 to 50 durometer, so methinks the 45A version might work best. He didn't have a cured sample, so I dumped a blob on a piece of wood. We'll see what it looks like on Tuesday.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Jeff Liebermann <jeffl@cruzio.com>: Jan 16 10:44AM -0800 >Is it simple on/off contacts or is change of R monitored for key "action"   <http://oi65.tinypic.com/14xdmo3.jpg> The piano keys on a synthesizer might require some form of velocity sensing which most assuredly is NOT resistive. The buttons in the above photo are for turning things on/off and are therefore simple on/off connections. <http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html>       -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

N_Cook <diverse@tcp.co.uk>: Jan 16 07:40PM On 16/01/2016 18:44, Jeff Liebermann wrote: > above photo are for turning things on/off and are therefore simple > on/off connections. > <http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html>   I don't know how many contacts are required. I just tried taking a standard simple 10x10mm footprint click switch apart , parts just clipped together. Cutting a disc of thin <1mm silicone rubber, placing over the dome contact and reassembling , the click noise and abrupt click action disappears, but still functions. If they can be soldered to the pcb, ignoring the resistive pads, then only a matter of fudging the right size and height of top protrusion to glue over the stem of the switches,if necessary . Well thats my halfpennyworth

"Gareth Magennis" <sound.service@btconnect.com>: Jan 16 08:32PM "N_Cook" wrote in message news:n7e66d$vm5$1@dont-email.me...   On 16/01/2016 18:44, Jeff Liebermann wrote: > above photo are for turning things on/off and are therefore simple > on/off connections. > <http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html>   I don't know how many contacts are required. I just tried taking a standard simple 10x10mm footprint click switch apart , parts just clipped together. Cutting a disc of thin <1mm silicone rubber, placing over the dome contact and reassembling , the click noise and abrupt click action disappears, but still functions. If they can be soldered to the pcb, ignoring the resistive pads, then only a matter of fudging the right size and height of top protrusion to glue over the stem of the switches,if necessary . Well thats my halfpennyworth               Look at the photo, I need to replace the 0-9 data entry keypad on the far right of the panel, and the four buttons to the left of it. http://www.vintagesynth.com/sci/stk.php     The customer has said he wants the keyboard for his own use, so doesn't require it to be restored to original condition, so I am now thinking I might be able to find a 16 way keypad and wire it directly to the switching matrix, and pretty much glue it to the top panel. (He now realises ripping out the old pads because they didn't work properly was not a good idea. I think he has been using a screwdriver to operate the pads)   It will need some hacking because from memory, 0 - 7 have a common line, 8 & 9 use part of another, and the other switches I think are kind of random in the matrix.       Gareth.

"Gareth Magennis" <sound.service@btconnect.com>: Jan 16 08:41PM "Kaz Kylheku" wrote in message news:20160115224710.851@kylheku.com...   > I would direct your juvenile rantings to Microsoft instead. > It is they who have made Live Mail do this, and they won't fix it.   Using Live Mail even though it sucks and you know it is *your* choice. Why *should* they fix it when hordes of lemmings will use a free piece of crap as-is? You're the reason they won't fix it.   The responsibility for conforming to Usenet guidelines is yours alone; you can't deliberately use some program you know is broken and blame it on the programmers.   *That* is juvenile; a seven-year-old can easily be found who has a more sophisticated view of the world than this.           Yawn.   Get over it. Everyone else can adjust and read it just fine.

Jeff Liebermann <jeffl@cruzio.com>: Jan 16 04:00PM -0800 On Sat, 16 Jan 2016 20:32:28 -0000, "Gareth Magennis" <sound.service@btconnect.com> wrote:   How to quote properly with Windoze Live Mail: <http://www.dusko-lolic.from.hr/wlmquote/> More: <https://www.google.com/#q=windows+live+mail+usenet+quote>   >(He now realises ripping out the old pads because they didn't work properly >was not a good idea. I think he has been using a screwdriver to operate the >pads)   Well, if you're going to butcher the synth, then it might be possible to just solder in some switches with a long shaft. Something like these: <http://www.ebay.com/itm/221708447229> Yes, that's 100 pcs for $1.74. I bought 1,000 and no problems. The extra long shaft is handy for attaching a push button. If it sticks through the synth panel, you win.   >It will need some hacking because from memory, 0 - 7 have a common line, 8 & >9 use part of another, and the other switches I think are kind of random in >the matrix.   No hacking required with the above suggestion.   Am I getting a commission on this deal?   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

"Gareth Magennis" <sound.service@btconnect.com>: Jan 17 12:48AM "Jeff Liebermann" wrote in message news:klll9bpdnqcscame7l7rifntjm1gksdbfo@4ax.com...   On Sat, 16 Jan 2016 20:32:28 -0000, "Gareth Magennis" <sound.service@btconnect.com> wrote:   How to quote properly with Windoze Live Mail: <http://www.dusko-lolic.from.hr/wlmquote/> More: <https://www.google.com/#q=windows+live+mail+usenet+quote>   >was not a good idea. I think he has been using a screwdriver to operate >the >pads)   Well, if you're going to butcher the synth, then it might be possible to just solder in some switches with a long shaft. Something like these: <http://www.ebay.com/itm/221708447229> Yes, that's 100 pcs for $1.74. I bought 1,000 and no problems. The extra long shaft is handy for attaching a push button. If it sticks through the synth panel, you win.   >& >9 use part of another, and the other switches I think are kind of random in >the matrix.   No hacking required with the above suggestion.   Am I getting a commission on this deal?           Er, no, because it is not possible to solder these switches, or even mount them, to the conductive pads on the PCB.     I am still in favour of a 16-way keypad glued to the synths top panel, with flying leads/ribbon cable (hidden beneath such keypad) attached directly to the keyscan ports.       Gareth.

Jeff Liebermann <jeffl@cruzio.com>: Jan 16 04:59PM -0800 On Sun, 17 Jan 2016 00:48:23 -0000, "Gareth Magennis"   >Er, no, because it is not possible to solder these switches, or even mount >them, to the conductive pads on the PCB.   They don't need a low resistance connection. Just a connection. You can probably glue them in place with some hot melt glue. Or, if you want something better, solder tiny squares of sheet copper to the switch legs, and glue that in place. If you like spending your customers money, try some conductive graphite flake or silver "paint" and bury that under a layer of hot melt glue.   >I am still in favour of a 16-way keypad glued to the synths top panel, with >flying leads/ribbon cable (hidden beneath such keypad) attached directly to >the keyscan ports.   Common decency, aesthetics, and my moral obligation to clean living prevent me from offering an opinion of that idea. Sure, it will work, but will be seriously ugly and messy. It's ok to fix something but when you're done, it has to look good. Perception is everything, which begs the question of whether the customer is going to pay for a hacked keypad fix.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

"Gareth Magennis" <sound.service@btconnect.com>: Jan 17 01:22AM "Jeff Liebermann" wrote in message news:sgpl9bhpp53216b7h0shbmqoq5b3iqlrhn@4ax.com...   On Sun, 17 Jan 2016 00:48:23 -0000, "Gareth Magennis"   >Er, no, because it is not possible to solder these switches, or even mount >them, to the conductive pads on the PCB.   They don't need a low resistance connection. Just a connection. You can probably glue them in place with some hot melt glue. Or, if you want something better, solder tiny squares of sheet copper to the switch legs, and glue that in place. If you like spending your customers money, try some conductive graphite flake or silver "paint" and bury that under a layer of hot melt glue.   >I am still in favour of a 16-way keypad glued to the synths top panel, with >flying leads/ribbon cable (hidden beneath such keypad) attached directly to >the keyscan ports.   Common decency, aesthetics, and my moral obligation to clean living prevent me from offering an opinion of that idea. Sure, it will work, but will be seriously ugly and messy. It's ok to fix something but when you're done, it has to look good. Perception is everything, which begs the question of whether the customer is going to pay for a hacked keypad fix.           Well, exactly. Though I'm privy to information you are not, being as I have talked to the customer.   He knows he has really f888ed up this keyboard, but is really only interested in having some way to program it, now he has destroyed the input capability. He just wants some way of using it in his studio, aesthetics are not part of the equation.   I'm thinking I could perhaps knock up a 16 way keypad and hardwire it in, say, 5 hours? (not counting the hours of research I am currently undertaking) Then I would be charging him something like 2 or 3 hours, and we would all be happy.       Sometimes Work and hobby, and just trying to help someone out, merge into something you actually might quite like to attempt!         Gareth.

whit3rd <whit3rd@gmail.com>: Jan 16 09:30PM -0800 On Saturday, January 16, 2016 at 5:40:15 PM UTC-8, Gareth Magennis wrote:     > I'm thinking I could perhaps knock up a 16 way keypad and hardwire it in, > say, 5 hours? (not counting the hours of research I am currently > undertaking)   Oh, just buy a 4x4 keyypad, they[re not completely unavailable   <https://www.adafruit.com/products/1611>   Hand-wiring would be one way. If the buttons magically line up, just cut the membrane part off and do a transplant.

"Gareth Magennis" <sound.service@btconnect.com>: Jan 16 09:03PM "N_Cook" wrote in message news:n7bapn$gku$1@dont-email.me...   For holding, through grommets, reverb tank to steel chassis, so not the usual small ones for DSP boards etc. You cannot reinsert, blind, as the 4 splay bits are permanently splayed out. Find a metal plate with holes the size to push each rivet in, to close back the 4 splays, then old soldering iron and hotmelt glue the 4 together. Reinsert through grommets and chassis, then the closer rivet, with more force than usual to break the hotmelt .         Hmmm, I've read that several times now and am none the wiser.   I have a picture of a reverb tank with rivets through grommets on a steel chassis, but then it goes all wibbly wobbly.     I would be inclined to use 4 x 3mm or 4mm bolts and locknuts.           Gareth.

Kaz Kylheku <kaz@kylheku.com>: Jan 16 11:08PM > Reinsert through grommets and chassis, then the closer rivet, with more > force than usual to break the hotmelt .   > Hmmm, I've read that several times now and am none the wiser.   He seems to have found a way to re-use splay rivets by squeezing together their splayed ends with a simple jig (metal with holes), and temporarily hot-gluing them together. The rivets can then be re-used. Applying the rivet fastener with "more force than usual" completes the job by breaking off the hot glue.

"Gareth Magennis" <sound.service@btconnect.com>: Jan 17 12:53AM "Kaz Kylheku" wrote in message news:20160116150159.899@kylheku.com...   > Reinsert through grommets and chassis, then the closer rivet, with more > force than usual to break the hotmelt .   > Hmmm, I've read that several times now and am none the wiser.   He seems to have found a way to re-use splay rivets by squeezing together their splayed ends with a simple jig (metal with holes), and temporarily hot-gluing them together. The rivets can then be re-used. Applying the rivet fastener with "more force than usual" completes the job by breaking off the hot glue.             Yeah, right, funny how you snipped all my context to suit your own agenda.   Prick.

John-Del <ohger1s@aol.com>: Jan 16 12:05PM -0800 On Saturday, January 16, 2016 at 11:42:50 AM UTC-5, Look165 wrote:   > > And just in case, here is the dataseet for the EEPROM:   > > http://www.esmt.com.tw/DB/manager/upload/F25L32QA%282S%29.pdf   > > Good luck!   It's a current production memory (at least within the last two years or so, hardly a museum piece.   I did order 10 of them through Alibaba and they arrived a couple of weeks ago.

Look165 <look165@numericable.fr>: Jan 17 12:49AM +0100 I used to work with those memories (2516 or 2532) in 1975 i.e. 40 years ago. You may find ones now...just check the date code (generally YYWW) !   John-Del a écrit :

johnwaynerocks691@gmail.com: Jan 16 10:44AM -0800 Hey ,can I buy a new circuit board for a rldv3282a

John-Del <ohger1s@aol.com>: Jan 16 12:03PM -0800 On Tuesday, October 22, 2013 at 4:08:19 PM UTC-4, SharpShooter wrote:   > I am unable to trace where/why the 5 volts from this board is NOT coming to the connector. There is another set of long connector on this main board which receives power from the power supply and that shows the relevant 12v and 5 v Dc at that point.   > So in short, the main-graphic board that also powers the dvd is not giving 5v dc output to the DVD player - which i believe also powers the switches - and thus the TV is perhaps frozen in standby mode ( I am not sure of that) No remote so I cannot take it out of the standby mode - also ALL the switches are non responsive.   > Any help will be appreciated.   It seems unlikely that you're getting only 90VDC across the PFC capacitor. If that's what you're getting, replace that cap. Ordinarily, you should be getting about 160VDC across that with a 120VAC in standby, and 325 to 375 with the TV on.   It also seems unlikely that you'd be getting normal secondary voltages if there was only 90V on the PFC cap, but anything is possible I guess.   The 5V for the DVD is a switched source and is not a pertinent test point for checking a dead TV. Most likely it's not sourced from the 5V standby but the 12V run through an on board dc-dc converter.   The first course of action is to verify the voltage on the PFC cap as it should never be anything less than 160. If it is, solve that first.   If it still doesn't start, check the main IC for runaway heat on plug in. These boards often get whacked through the HDMI ports and the main IC will short and get hot in a hurry. If that's what you're getting, it's easier to replace the board.   If not, good chance the firmware is corrupt. Unfortunately, RCA (whoever it is now) will not send you the .bin file. Might be an eeprom available on ebay.

John Heath <heathjohn2@gmail.com>: Jan 16 12:27PM -0800 On Saturday, January 16, 2016 at 3:03:05 PM UTC-5, John-Del wrote:   > The first course of action is to verify the voltage on the PFC cap as it should never be anything less than 160. If it is, solve that first.   > If it still doesn't start, check the main IC for runaway heat on plug in. These boards often get whacked through the HDMI ports and the main IC will short and get hot in a hurry. If that's what you're getting, it's easier to replace the board.   > If not, good chance the firmware is corrupt. Unfortunately, RCA (whoever it is now) will not send you the .bin file. Might be an eeprom available on ebay.   I second that.   450v 68uF capacitor I get 90v DC.   That sounds fishy. I would snoop around that area looking for flat caps , burned resisters or open fuse.   I have 5 cents that says its a flat cap.   Also check for cold solder around the switching transformers. They are heavy and can wiggle lose if the TV is next to a home theater sub bass speaker , vibration.

Michael Black <et472@ncf.ca>: Jan 16 05:57PM -0500

John-Del <ohger1s@aol.com>: Jan 16 03:31PM -0800 On Saturday, January 16, 2016 at 5:53:02 PM UTC-5, Michael Black wrote:   > DOn't reply to old posts just because google lets you, don't reply to old > posts.   > Michael   We certainly wouldn't have if we had noticed the "boob" was bumping an old thread. Okay, so we responded to a new post that was in a thread bumped by another poster. So we are guilty for not tracing back farther to check earlier posts for dates posted. Hardly worthy of scorn.   This happens a lot. Someone asks the original poster if they are still selling that amplifier they listed 14 years ago, and others respond afterwards. It happens. The first is indeed a boob, the rest can be called inattentive if you feel the need to call them out.   Besides, many solutions to problems can be resolved by looking at past posts. Anyone with a similar problem may find value in the added info. In this case, voltage across the PFC capacitor is a universal situation that affects many modern consumer electronic items.   And it's not like this group is a huge beehive of activity anymore like it was 15 years ago.

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