Can anyone fix a Lexicon RV-8 for audiodon?

[LexDM3]

I'm hoping that some major digital/analog wizard among us may be able to help out an AKer going through tough times. Can anyone troubleshoot and repair a Lexicon RV-8 or do you know anyone who can? Or does anyone have a connection with Harman, Lexicon or one of their repair centers? If so, please let me know.

Our good friend and tube wizard audiodon has ALS and is no longer able to work on audio gear. We have sold off almost all of his tube projects. Don loves his audio and has a 2004 vintage Lexicon RV-8 AV receiver that was top of the line when it came out. He bought it used about 5 years ago.

The RV-8 quit a couple of months ago. Don checked with someone he knows and found that a Harman/Lexicon service center wanted $500 just to look at it. I said I'd give it a try, thinking it was likely a power supply issue since the unit doesn't come up at all and has only a few front panel lamps on.

All fuses are good and nothing is obviously cooked so I started checking the power supplies. The unit has a Crown-sourced conventional PS to power the 7 Crown 140W amp channels and a triple output switcher to power the logic and I/O modules. The switcher's 5VDC output was only at 3.6V under a test load so I subbed in an external 5V supply, hoping that might do it.

No luck. I believe that this unit has problems on the main logic/control board but I do not have the skills, tools, information or time needed to bring it back to life.

If anyone can help Don out on this, let me know. I have the unit and can get the original box from Don so I can ship it.

Alternately, if anyone would like to buy this as a fixer-upper, please let me know. (Mods, please don't delete this thread for that. I'm trying to help Don. Thanks.)

The AK community has been great to Don and he and I really appreciate that. Many thanks. --Dan

 

[LexDM3]

Bump...

 

[audiodon]

Well, we tried.

 

[wlhd1610]

I have saved a few Citation XX holy grail amps from the boneyard but they only have 2 small driver boards using SMD technology,the rest being conventional boards.

This one is ALL SMD with proprietary logic processors and lack of publicly available service manuals which is probably why you haven't received any responses.

I looked around and see that several have sold recently on eBay($410 and $1275) and that there are a few currently available in the US($1200 and $1500).

Bob

 

[steph_gaynor]

oh, now I know why Don has mentioned how much easier it is to service vintage tube gear with point to point wiring vs. transistors. I did not know there was a problem with the big multichannel Lexicon. I don't know if you still have it but it would be well worth talking to Jim Fuller about it. His fees are reasonable. And, while he is located in VT, he travels to Boston area weekly.

https://www.facebook.com/RestorationAudio/

 

[KentTeffeteller]

If there was any way I could have repaired this, I would have done so without charge. audiodon is an awesome gentleman.

 

[LexDM3]

Thanks to Stephanie, Kent, and GD70 for your help and suggestions. I'll contact Jim Fuller and Tom B. There are some tricky things about the RV-8:

- It's a very complex hybrid digital system with a ton of computing stuff on it that looks fairly proprietary. That's not an ordinary Windows PC on those PCBs.

- I can't find decent documentation on it. There are some schematics in the Rev. 0 service manual that I found online but it's not enough. Lexicon/Harman won't send me more info. They told me to take it to an authorized service station. It's probably not worth repairing that way.

- The circuit boards are densely packed with Surface Mount Devices (SMDs). Those are very tough to work on, a league beyond through-hole printed circuit boards.

The three points above are why I'm not able to fix it. I'll try Jim and Tom.

Thanks again. --Dan

 

[NAD80]

SMD work in really hard to do without a schematic and PCB layout. Plus IC/micro processor pin out diagrams are needed to really understand how the circuit is working. And this is what I do for a living. Never mind bad solder connections to SMD parts that degrade over time. Have a display in the stock cd/radio in my 06 mercury milan that only works when it wants. Possible bad SMD resistor connection to the PCB I've heard. Good luck in getting it repaired for him.

 

[Eriklhayes]

I have a RV-8 with a similar problem. When I turn on the power switch, only the blue and red led on the front panel turn on. Let me know if you have discovered anything that can help!
Thanks,
Erik

 

[Eriklhayes]

I have the service manual if you need it. You can get if from a google search. I suspect the reset chip u31 as i am not getting any of the main board leds. In other words, the reset is stuck on, resetting all of the chips. It is delicate work but I think that I can replace it. I am not seeing any power on the toroid power supply board, but I suspect that the main board is not turning on the relays to power it up. I am also considering "oven baking" the board if there are SMD connections that need to be re-soldered. Any advice on this?

 

[whoaru99]

... I am also considering "oven baking" the board if there are SMD connections that need to be re-soldered. Any advice on this?

One way to look at, it's probably not worth authorized service center repair cost and it doesn't work as-is. What is there to lose by trying?

 

[Nashou66]

Guys , try posting over at Repairalmostanything.com MisterMac here ia Master tech there, He might be able to guide you through the repair.


Athanasios

 

[Eriklhayes]

I have found that the 5V DC relay on the crown amp power supply is not engaging although it has 5v on the coil. I am planning to replace it! Will let you know if that does it.

 

[Eriklhayes]

I wish that I had a schematic of the amp power supply in order to check the diodes and transistors on the board.

 

[Eriklhayes]

Well, it was not the relay. I have noticed on the main control/processor board, that none of the LEDs are lighting up. I have checked all of the power supply voltages and they are OK. Looking for options/ideas/experience at this point!?

 

[LexDM3]

Hi Erik. Good detective work and I'm sorry you haven't (yet) found the problem. I have t been into the Lexicon for a while but my sense was that the main logic board had to power up and pass diagnostics before it turned on the relay(s) to start up the amplifier power supply.

On Don's unit, the main logic board never initializes up so the amp PS doesn't start up. No surprise. I suppose I could try to pull the PS relay drive signals high to see if the PS turns on but there's not much point in doing that if the rest of the unit doesn't work.

FWIW, I found that the switching supply on the left front of the unit had a low +5V output when I pulled it and measured all 3 outputs with resistive loads. Hoping I had found a simple problem, I subbed in an external 5V supply. No joy.

 

[Eriklhayes]

We will figure this out! Today I went out and purchase a hot air soldering rework station and went over all of the main logic board connections. No luck after power up. I have the same red-blue light that comes on and not LEDs on the main logic board. I found a similar power supply and have ordered it. I did notice that the -15V power supply was higher than the limits in the service manual. Are you getting LEDs on the main logic board?

 

[LexDM3]

I'm getting only a few LEDs on and the cooling fans running. A red LED associated with the IR port is on fairly brightly. The RV-8 manual says the red LED indicates A/D converter overloading. I suspect it means little or nothing now.

There are two other LEDs glowing weakly on the front panel. One is red and is at "Sat" and the other is blue and is on the Amp 7 indicator. The LCD display doesn't light up at all. See the attached picture.

I don't remember seeing any LEDs lit up on the main PCB. The unit is closed up now. I can open it up tomorrow if that would be helpful.

It sounds like the two units have a similar problem. Here's some information on the switching supply. I couldn't find a schematic for it.

 

[for_p1]

I'm getting only a few LEDs on and the cooling fans running. A red LED is on fairly brightly. I think that one may normally show IR activity from the remote but I'm not sure of that. There are two others glowing weakly on the front panel. One is red and is at "Sat" and the other is blue and is on the Amp 7 indicator. The LCD display doesn't light up at all. See the attached picture.

I don't remember seeing any LEDs lit up on the main PCB. The unit is closed up now. I can open it up tomorrow if that would be helpful.

It sounds like the two units have a similar problem. Here's some information on the switching supply. I couldn't find a schematic for it.

View attachment 845104

In devices like this there are two power supplies: main one and also one for stand-by circuit. You need to check one for stand-by and they see if stand-by processor tries to activate main power when ON command is sent from remote. But without official service manual with full schematic and factory diagnostic procedure it is almost impossible to work on that kind of devices.

Authorized repair centers do not do component level repair anymore - they just install new boards when defective is found.

 

[LexDM3]

I think this has way bigger problems than just not being able to activate when the remote is pressed. There is a front panel power button and that does nothing.

Yes, nobody does component level troubleshooting on a complex SMD board like the main PCB in the RV-8. I'd love to borrow a set of boards and swap them in to isolate the bad one(s) but that's not possible since Lexicon won't give me any help. They say to take it to a service center. That's certainly going to be very expensive and not worth it in this case.