kuznetz 4 Posted August 25, 2016 Share Posted August 25, 2016 hi group I am new here but an old Carver fan picked up this AV806x on Ebay as is , 150 , three channels dead probably 4 , rca's & spkr terminals bashed / bent but all else looks original inside , I can buy new boards for any of the 5 slave modules but not the master which of course is bad this board has all the connections for the RC5 remote and that multi pin controller connection which I don't need or any bridging this master has extra components onboard at the rear however other than that it seems pretty similar to the slaves wondering if I could just replace the master w a new slave , ...? a bit concerned that it may not work ...as in the slaves will be looking for a master ...? the next option is to rebuild the whole board , I have read of a few other members having trouble sourcing caps that fit etc ....if anyone has thoughts about this it will be mighty appreciated thanks Bernie 4 Link to comment Share on other sites More sharing options...
PMAT 1,838 Posted August 25, 2016 Share Posted August 25, 2016 Welcome to the site. Help will come. 1 Link to comment Share on other sites More sharing options...
aslan7 954 Posted August 25, 2016 Share Posted August 25, 2016 Yes welcome Kuznetz! Great to have a long time Carver fan on board the carver express. We love all things audio. Do you have a picture of your Av806x? We shall get her firing on all cylinders in no time. The technicians here are amazing and I'm sure you will fit right in with your knowledge. And by the way, it's great to see a piece of Carver equipment get resurrected. Thank you for your efforts and posting ! Again welcome aboard Link to comment Share on other sites More sharing options...
maytag 795 Posted August 25, 2016 Share Posted August 25, 2016 Thanks for posting. Welcome to the group. Enormous amount of information on this site and everyone is willing to share/help. I'm looking at Av806 as well. I will be following your progress. What do you plan to use it for? Link to comment Share on other sites More sharing options...
fill35U 1,845 Posted August 25, 2016 Share Posted August 25, 2016 The schematics we have aren't the easiest to read, at least with my software. And it looks to me like they're incomplete in regards to the details of how the slave modules are different and how they link together. However, based on what I can make out, and from photos of the interior: I *guess* that you could run her with no master module, or with a slave substituted for the master, if you could generate the "power on" signal to send to the slaves. I'm pretty sure that signal is generated in the master, and sent to all the slaves at the same time via the grey ribbon cable at the front of the amp boards. That same signal is what makes the "power on" (green) LED light, and is sent to the LED board by gray ribbon cable. The LED board gets a 3-conductor ribbon, since it needs to show "standby" status as well(LED lights red). But the ribbon from the master to all the slaves is 2-conductor. I think that 2-conductor cable carries +15V on Pin 1 of the connector (outside pin), and in "power on" it makes Pin 2(middle pin) go to 0V, lighting the LED and telling the slaves to turn on. BTW "turn on" may just involve input muting and output relays, the amp sections probably stay idling warm in "standby". Each slave module should generate its own regulated +15V supply as the master does. So it should be easy to pick one slave module and make it act like a master: tie the +15V from the regulator to Pin 1, and tie Pin 2 to ground. If you're lucky, they used the same boards for masters and slaves, just populated them accordingly, so you'll have lots of free pads or jumper points to play with. That's my best guess! It would be nice to have a working amp to examine to know for sure. Good luck! 2 Link to comment Share on other sites More sharing options...
fill35U 1,845 Posted August 25, 2016 Share Posted August 25, 2016 Thinking about it, you might want to put a 33R 1W metal film resistor in series with the +15V trigger from the "acting master" module. Before it gets to the circuit where the module triggers itself! That'll limit fault current in case of serious problem, and hopefully blow open if the fault continues for more than a few seconds. At 20mA per module (including the "acting master"), it shouldn't amount to more than a 4V drop. I'd expect that 11V would still be sufficient, and that signalling each module wouldn't take more than 20mA. Obviously, you want to try this scheme on just the "new master" alone first, to see if it can turn itself on. Then add modules one at a time, monitoring the +15V trigger for consistent but not excessive droop. You could also pull down that +15V trigger with various resistances (or use a variable power supply) to find out what minimum voltage is acceptable to turn the slaves on and keep them on. Link to comment Share on other sites More sharing options...
peck555 366 Posted August 25, 2016 Share Posted August 25, 2016 There is 6 channel set of amp modules for sale on eBay item<91954231263 2 Link to comment Share on other sites More sharing options...
fill35U 1,845 Posted August 25, 2016 Share Posted August 25, 2016 There is 6 channel set of amp modules for sale on eBay item 191954231263 FIFY! Thanks, Peck! $390 for all six slave modules, same seller has slaves singly for $75 each. What's this about "Marantz MA-500"? Ah! It's a single one of the *same* AV-806x slave modules in a little monoblock chassis! Maybe a service manual for the MA-500 would help? Might explain why the module schematic in the Carver service manual looks like it's from a completely different manual... 1 Link to comment Share on other sites More sharing options...
kuznetz 4 Posted August 26, 2016 Author Share Posted August 26, 2016 thanks guys for the fast responses , all appreciated , so I will purchase 6 NOS slave boards in less than a week my SO and I will be away till October when I get back I will start to tear the amp down and proceed as Fill suggested , I don't have a scope just a good DMM so hope I can piece it together the amp will power active 3 way spkrs , a channel per driver cheers Bernie Link to comment Share on other sites More sharing options...
kuznetz 4 Posted August 26, 2016 Author Share Posted August 26, 2016 interesting I should have noticed the MA500 ...I just saw Carver ...tunnel vision I guess however all the reviews I have read about the 806 were favorable , Bob just slipped in something else in to the case just DL'ed the schematic and sure enough its the same . I want to believe that he did something to make it special Link to comment Share on other sites More sharing options...
Balok 1,397 Posted August 26, 2016 Share Posted August 26, 2016 I'm pretty sure Bob left Carver Corporation before the AV806x came out. 1 Link to comment Share on other sites More sharing options...
fill35U 1,845 Posted August 26, 2016 Share Posted August 26, 2016 Oh wow, that schematic in the AV-806x manual *is* the page from the Marantz MA-500 manual! The MA-500 manual is much more legible than our copy, and fills in a lot of blanks elsewhere. They really complicated setting the bias, do they expect you to use a stopwatch? Bob was long gone by the time the AV-806x came out. Who knows who licensed from who? It's a pretty conventional design, after you take away all the specialized chips that run everything. It certainly didn't have anything to do with the AV-405 of the year before, nor the AV-705x of the year after. Link to comment Share on other sites More sharing options...
kuznetz 4 Posted August 27, 2016 Author Share Posted August 27, 2016 well I am getting a fast education about the later history of BC and Carver ....I had both the PL 700B & 400 in the 70s always loved his moxie later got distracted w life I'm retired and getting back into my hobby /illness and mostly having good fun on small money , so now I have a Carver badged Marantz multi channel , I will get it working and go from there my active spkrs need 6 channels so will see how it powers them , now I have 3 adcoms down the road maybe I will consider something like 3 updated M1.0T's ....? cheers Link to comment Share on other sites More sharing options...
Java1960 21 Posted October 30, 2020 Share Posted October 30, 2020 So is it determined that the board from the Marantz MA500 would work in the AV-806x? I have one with channel one not working 1 Link to comment Share on other sites More sharing options...
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