tag:blogger.com,1999:blog-5053304027701850753.post7444106519694472359..comments2024-03-29T04:51:00.683-07:00Comments on Joe's Technology Blog: Fixing Denon PMA-980R Input / Volume Selector "Jumpiness" (English)Johanneshttp://www.blogger.com/profile/08796700991875418529noreply@blogger.comBlogger23125tag:blogger.com,1999:blog-5053304027701850753.post-8237979402965163002024-01-30T02:49:29.420-08:002024-01-30T02:49:29.420-08:00Hi, I think that there must be some interference o...Hi, I think that there must be some interference or crosstalk between the two CPU pins (pin 24 = function / input selector, pin 25 = speaker output selector). The two dials have no connection between them except the +5V and the GND rails, between which they dial from a resistor ladder. Please contact me via e-mail johannesfranke74@gmail.com, I can show you the section in question in the service manual. You can also download the manual from here: https://www.electronica-pt.com/esquema/audio/denon-audio/denon-pma-980r-41490/<br />The section in question is on pages 27 and 28.Joenoreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-12897302425966671892024-01-29T07:15:43.929-08:002024-01-29T07:15:43.929-08:00Hello,
I have a similar problem, but I'm not s...Hello,<br />I have a similar problem, but I'm not sure if it's in these selectors or the processor.<br />The problem is that when you use one selector, the setting of the other one changes.<br />What do you think? Could it be a cpu problem or is the cause as described above in your blog?<br /><br />greetingsAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-57617300900512477582021-11-30T11:25:13.310-08:002021-11-30T11:25:13.310-08:00Hi there, well it's certainly a different prob...Hi there, well it's certainly a different problem than the one discussed here. I would recommend you to download the service manual, it's pretty well-written and there is a lot of information and schematics. The PMA-980 has two transistors (types are B1274 and D1813) which get very hot in operation so they basically desolder themselves. Look for TR844 and TR843. Look for the thick copper bar to the right of the heat sinks. The transistors in question are near it on both sides. Check their soldering first, it could fix your issue. I put them on wires and bolted them to the heat sinks, and would recommend everyone to do so. It was not a good idea to leave them hanging there with no heat sink at all when their operation temperature is around 80°C. Other than that, there are some contacts in the signal path that you might want to trace. If there is a huge difference between "source direct" and the other mode, check the front panel PCB where the potentiometers for balance, bass and treble are located. They might need some cleaning. I don't know about the volume control though. If the knob stops turning after it reached a quarter of its way, I would assume that there is a problem with the gears between the motor and knob. No idea if that is fixable. There are no original parts available any longer from Denon.<br />Hope this helps. Please share if you can find anything. Thank you!<br />Cheers,<br />JoeJohanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-74802346322151904772021-11-29T11:05:52.840-08:002021-11-29T11:05:52.840-08:00good day, I have a PMA980r, one side works with a ...good day, I have a PMA980r, one side works with a background noise and the other channel does not give sound. The volume control does not work, it does not go up nor does it go down. With the remote control the volume knob only moves up to a quarter of the volume, which could be happening with this DenonPHIL29EShttps://www.blogger.com/profile/02933107959252953329noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-83350709606094974192021-08-17T00:48:32.629-07:002021-08-17T00:48:32.629-07:00Hi there, well, trace from the beginning, I would ...Hi there, well, trace from the beginning, I would suggest. First be sure the source (connected via stereo RCA) is actually playing something and that the amplifier is doubtlessly set to play something (not muted, correct input selected, speaker output active, volume > 0). If that's the case, check whether the input selection relays are clicking along as you select a source. If not, could it be that you have forgotten to plug one of the connectors back into the front panel pcb? Page 13 of the service manual (https://www.audioservicemanuals.com/d/denon/denon-pma/denon-pma-980r/212796-denon-pma-980r-service-manual) shows the way signals are routed through the amplifier. Sorry, the service manual is only available in German for some odd reason but the chart is easy to understand. It may me best to trace the input signal along the way. If everything worked before the repair and now there is no sound, it's very likely that it's just a loose connection, not anything broken. Hope this helps. Good luck!Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-2757578996112719252021-08-16T10:32:02.049-07:002021-08-16T10:32:02.049-07:00Hi Johannes,
Thanks for this great manual to fix ...Hi Johannes,<br /><br />Thanks for this great manual to fix the speakers and input selector switch. <br />Nevertheless, cleaning the switches and reassemble the Denon 980r, the amplifier does not produce a sound.<br />All functions on the front panel work fine. Also by using the remote control. <br /><br />Do you have any idea why the amplifier does not amplify anymore?Anonymoushttps://www.blogger.com/profile/14730263560466271730noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-64654623987748598142020-11-03T13:15:28.880-08:002020-11-03T13:15:28.880-08:00By the way, I just found a post about the PMA-2000...By the way, I just found a post about the PMA-2000AE which has almost exactly the same part as the one described here: https://derreparateur.ch/2017/10/12/denon-pma-2000e-input-selector-springt/<br />(it's German but nevermind, this is a good hint, and it also shows how to go on). Apparently it's a lot easier to get to the part in question in the newer amps, compared to the 980R. Hope this helps!Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-77846514627131727022020-11-03T05:01:56.953-08:002020-11-03T05:01:56.953-08:00hi there, sorry, no idea if it is a similar part. ...hi there, sorry, no idea if it is a similar part. if it is, don't worry about spare parts, I don't think you can find them anywhere. just clean the part you already have, as described here. Cheers, JoeJohanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-52884485169492176392020-11-03T04:44:48.540-08:002020-11-03T04:44:48.540-08:00Hi. Got pma1500ae that jumps channels. Assume it&#...Hi. Got pma1500ae that jumps channels. Assume it's the same procedure? Where Do I get the spare part?Anonymoushttps://www.blogger.com/profile/04441127740428379605noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-29773402227244349772020-07-21T09:29:47.476-07:002020-07-21T09:29:47.476-07:00Great, thumbs up to you and thanks for the feedbac...Great, thumbs up to you and thanks for the feedback!Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-26309064629478180982020-07-21T09:27:16.670-07:002020-07-21T09:27:16.670-07:00Dear Johannes,
Thank you for this. I have a Denon...Dear Johannes,<br /><br />Thank you for this. I have a Denon PMA 6.5 amplifier with a similar input selection knob, which was jumping between states as well. Cleaned it this morning and it looks like the problem is gone.<br /><br />I've had another problem with my amplifier, where the output volume was different between the two speakers. That turned out to be the output protection relay. There probably got some dirt in the relay, causing it not to make fully contact for one of the speaker channels. I fixed that some time ago by replacing the relay.<br /><br />So now I have a fully functional amplifier again. :)<br /><br />Kind regards,<br />SamuelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-23108713133766948742019-07-22T15:58:48.403-07:002019-07-22T15:58:48.403-07:00So.. finally I got it done. And it works like a ch...So.. finally I got it done. And it works like a charm. Thanks a lot, your blog was very helpful, at least helping to get the courage to even start with it. <br />Now, I am thinking of even complete re-cap and even the opamp swap... maybe I am about to write a blog as well soon...:)alias_mkhttps://www.blogger.com/profile/09664113866547846375noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-22342742826765878742019-07-05T00:29:58.995-07:002019-07-05T00:29:58.995-07:00Cool, and well done! May you enjoy the results for...Cool, and well done! May you enjoy the results for many years to come.Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-60629030054264893182019-07-04T14:24:43.024-07:002019-07-04T14:24:43.024-07:00dear Johannes,
many thanks for your detailed guide...dear Johannes,<br />many thanks for your detailed guide, you have done a good job.<br />I have just completed your procedure and the relays seem to have stopped the crazy clicking and the machine stopped changing the active input deliberately.<br />I tried to open the Amp before, but did not get too far. <br />It really did not take too much time to fix - I did not have to hesitate or try to find anything suspicious.<br />VIELEN DANK<br />Gruesse<br />Milan - SlovakiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-16983695021383380172019-03-27T00:00:46.833-07:002019-03-27T00:00:46.833-07:00Gracias, lo intentare, haber si no lo estropeo. Y ...Gracias, lo intentare, haber si no lo estropeo. Y llevarlo ccon un tecnico, en mi localidad no son tan confiables :(alencatrolhttps://www.blogger.com/profile/14393106756837442315noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-72921242215564499302019-03-14T01:25:12.200-07:002019-03-14T01:25:12.200-07:00Probablemente es el mismo tema discutido aquí. Int...Probablemente es el mismo tema discutido aquí. Intente limpiar las perillas giratorias desde el interior como se describe. Tienes una buena posibilidad de curar el problema de esta manera. ¡Buena suerte!Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-68340393000586174062019-03-13T22:30:05.710-07:002019-03-13T22:30:05.710-07:00Hola tengo el pma 980r, el problema que tengo es c...Hola tengo el pma 980r, el problema que tengo es con imput, de estar en AUX brinca a DAP TAPE 2, enveces funciona bien y enveces lo brinca cada 10 min aproximadamente. Que podria ser la fallaalencatrolhttps://www.blogger.com/profile/14393106756837442315noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-73208543499255898862018-09-06T01:30:11.784-07:002018-09-06T01:30:11.784-07:00Hi Jose, sorry, I have not seen any comments to be...Hi Jose, sorry, I have not seen any comments to be moderated for a long time.<br />The record selector is SW801 on the mainboard. It is a rather long multi-ganged switch that is actuated from the front panel knob via a Bowden wire. If you want to clean it up, I would recommend using contact spray cleaner first because it is a hell of work to desolder and disassemble it. Actually I have doubts whether it would ever go back together once you disassembled it.<br />Just apply a good amount of contact spray and go through all record selector inputs multiple times. The scratching should go away or at least reduce. Apply spray multiple times if needed.<br />You can contact me at johannesfranke74@gmail.com if you like :o)<br /><br />Regards<br />JoeJohanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-55809905736149081572018-05-29T11:59:51.288-07:002018-05-29T11:59:51.288-07:00Hi Johannes,
Thanks for the article, very compreh...Hi Johannes,<br /><br />Thanks for the article, very comprehensive. <br />I ha a little doubt. I have the Rec Selector and when I try to select diferent font, the audio scratches. I'm wondering how to dissasembly the cable from the record selector to clean correctly. If you want I can send you photos.<br /><br />Kind regards,<br /><br />Jose ManuelAnonymoushttps://www.blogger.com/profile/16266156628556931674noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-75508018802479834332018-05-02T05:12:12.460-07:002018-05-02T05:12:12.460-07:00Hi Johannes, thank you for your answer - and I apo...Hi Johannes, thank you for your answer - and I apologize for answering back after such a long time - but I meant it for subwoofer. Not that necessary, but eventually useful. <br />Seems like I am about to repair this amp soon, the problem is obviously the one described in your blog. Thanks again for sharing your experience.<br />Regards,<br />Markoalias_mkhttps://www.blogger.com/profile/09664113866547846375noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-6650043158199866752017-08-08T02:17:30.805-07:002017-08-08T02:17:30.805-07:00Hi Johannes,
Thanks for the article, very compreh...Hi Johannes,<br /><br />Thanks for the article, very comprehensive. But if I may, I’d like to offer people googling this problem an easy alternative fix.<br /><br />I have found a way to eliminate the 'jumpiness' without even needing to open the lid on the amp. All you need is a white marker pen, and the remote. The result is you will never have it jump ever again; the downside is you have to stop using the selector knob and only use the remote. But if you can handle that, read on!.<br /><br />I have had my amp for 21 years, and it’s still going strong. I love how reliable it has been. <br />I too, have had it apart a number of times over the past 5 or so years (since the jumpiness started) , cleaning the selector rotor contacts (both the speaker and function selector). Only to find the jumpiness seems to creep back and at random times. <br /><br />What I discovered was that sometimes the jumpiness was worse than other times, and began to wonder if it became dependant on where the knob was sitting at. I figured out that of the 12 positions of the selector switches, one of them shorts the selection input on main IC to GROUND. When it's at ground, the IC cannot change its state, you have no resistor ladder, no voltage divider, no more jumpiness!<br /><br />(On the IC I'm referring to inputs #24-Function and #25-SP (Speaker Select) - as per your schematic where you have highlighted these lines green and orange).<br /><br />I worked out which knob position sets the IC inputs to ground, marked it carefully and elegantly with some white paint. And now just use the remote to select the speakers or function - and have never had it play up since!<br /><br />I figured out that the jumpiness gets worse the higher up the resistor ladder you climb. From the 'ground' knob position, as you turn the knob anti-clockwise, it climbs the ladder, making the input more and more unstable. If you turn it one click clockwise from the 'ground' position you are at the top of the ladder and the jumpiness is at its worse. <br /><br />So, all you need to do is place the selector switches at the 'ground' position, mark it with white paint (or however you choose) because otherwise you’ll accidentally use your hand to move it around and not recall where the ground position is, and then only ever use the remote to change the speaker or function settings (a bit painful sometimes when you can’t find the remote, but worth it!). <br /><br />I'm not sure how to attach a photo, so I'll just explain where the 'magic ground position' - once you pull the speaker or function selector knob off you'll see the knob-post has a flat side to it, just make sure that's pointing at 4 o'clock (or 120 degrees).<br /><br />I hope to get another 21 years out of it now!<br />Ben <br />New Zealand<br />Anonymoushttps://www.blogger.com/profile/04868113747038719661noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-34946885584748321432017-02-04T06:22:55.203-08:002017-02-04T06:22:55.203-08:00Thanks for the feedback.
Why would you want a pre-...Thanks for the feedback.<br />Why would you want a pre-out? Do you have a dedicated power amplifier and plan to use the PMA-980R only as the pre-amp? The power amp section in the PMA-980R is excellent, so why not use that? It would be a shame to use only the pre-amp section of it, and also doesn't make much sense regarding energy consumption.<br />If the power amplifier inside the PMA-980R is not good enough for your purposes, then the pre-amp section probably isn't, too. So better consider a dedicated pre-amp in that case.<br />Probably it is possible to pick up the selected input somewhere inside to branch off a pre-out but really, I wouldn't know what to do with it.<br />In case I misunderstood and you actually want to use the PMA-980R as your power amp, but have a different device for input selection, I'd just use the CD input, connect the pre-amp to the CD jacks, and leave it at that.Johanneshttps://www.blogger.com/profile/08796700991875418529noreply@blogger.comtag:blogger.com,1999:blog-5053304027701850753.post-20140802035925391322017-02-04T04:14:05.056-08:002017-02-04T04:14:05.056-08:00Great article, thank you very much!
Could you also...Great article, thank you very much!<br />Could you also give a hint how to add and connect pre-out outputs to this particular amplifier? Thanks.<br />Markoalias_mkhttps://www.blogger.com/profile/09664113866547846375noreply@blogger.com