Denon DVD-2900 repairs and mods

pmckeealaska

Sorry, but who is George??

ben62670

George Daniels.

pmckeealaska

Got thanks. Dont know how I missed that one!

ben62670

http://www.polkaudio.com/forums/showthread.php?t=89966

pmckeealaska

Man, I dont know...I looked at the link and all the pics and it doesnt seem stupidly simple to me at all. I find these exceedingly intimidating from the standpoint of someone who has zero experience with sound boards and any electrical work. Is there a diagram I can use to follow what I'm seeing in the link pictures?

pmckeealaska

Just to be clear, in the link, Im seeing the top (brown) and bottom (green) of the sound board, yes?

You replaced the stock OpAmps with better units. I can see that, but I dont see the cheap electrolytic caps you said you replaced. I guess if I had a diagram, it might be easier to understand?

What are the two blue things I see on the bottom of the sound board (jesus I feel dumb right about now).

ben62670

I tried to find the service manual. You can find lots of info on DIYaudio.

pmckeealaska

Yep, I justed joined there. Lots of info with pics but I didnt really see anything with a step by step guide and pics. Without that, I fear I'd be pretty much screwed! I'm a wildlife biologist. Need a grizzly bear collared, I'm your man, but this audio stuff is greek to me.

BTW, I've noticed that my original problem with freezing DVD-A discs in surround only seems to occur when I've been using the Denon for a bit. When I use it cold, no problems...WTF?

ben62670

The brown board is the audio board. I replaced the electrolytics with Polycaps. I later tried it without the caps and basically jumped from the OpAmp to the L/R jacks using a 100r resistor.

pmckeealaska

In researching the 2900, it seems the stock laser transport is prone to failure (might be the problem I'm experiencing?). Is it fairly straight forward to replace? Perhaps thats where I should start since thats where this thread started?

Though I am happy with the audio quality from the 2900, my ears are good enough to detect some muddied mid range on some recordings, particularly SACD's. DVD-A is gorgeous, but SACD not so much. Perhaps some mod to improve SACD playback should be my first attempt? First things first though....a service manual.

ben62670

I have never replaced a laser before. The SACD shares the audio section with the RedBook player

pmckeealaska

Got it. Again, perhaps a manual is in order. However, I did find a place here in Anchorage that does service Denon's today. Very suprised to find a place up here in Alaska! $45 for a first look to see what's wrong.....not sure if its worth the $$ if 2900's are going for $200 and less used these days?

ben62670

I would be leaning twords having it serviced. If you get another player it may have issues.

pmckeealaska

Agreed. I may proceed with that first. Chris Johnson with parts connexion just emailed me with a quote in their Level 1 mods and it's $895 installed. It includes:

Our Level-1 mod installs:
We upgrade the critical I/V conversion and output buffer op amps, replacing the stock parts (about 50 cents each) with the best single and dual op amps available (Burr-Brown OPA-627's, requiring a dual DIP to single SMT adaptor pcb - and SMT packaged-only Analog Devices AD8620) which are 50 to 100 times as expensive as the stock parts. These upgrades dramatically enhance both the unit's technical and subjective audio performance. Our mod uses 2 of our custom Analog Devices AD8620 and 2 of our custom Burr-Brown OPA627 adapter pcb's.

The main output RCA jack pair is changed from the cheap stamped metal and plastic types to precious machined Vampire RCA jacks, using a base material of OFC-Copper (3.5 times more conductive than brass), and direct gold plating without any intermediate nickel.

The output signal exits not via a miniscule tin/lead plated pcb trace, but by pure 99.99% 23 awg solid-core silver DH Labs wire with Teflon insulation.

22 critical signal-path resistors are upgraded to precision Japanese-made Riken Ohm Carbon Comp types with gold-plated copper leads to replace cheap magnetic Taiwanese units.

All critical caps are upgraded to the best film and electrolytic types - 2 Rel-Cap Teflon bypass caps; 4 BlackGate KF Series coupling caps; and 10 polystyrene analog filter caps.

Chassis resonances are dampened with 1 sq.ft of SoundCoat and external vibrations have been isolated via four compliant EAR Sorbothane feet.

The power supply is upgraded with 6 BlackGate FK and NX series electrolytic caps and all critical analog supply diodes (generic stock quality) are replaced with ultra-fast soft-recovery Fred type diodes (1 Telefunken and 5 IR Hexfreds).

We use WBT 4% silver solder for all parts replacements.

The mod takes upwards of 6.5 hours to complete and carries a 90-day warranty.


Thats way more $$ than I really wanted to spend. How much of this is doable myself?

ben62670

That is a lot of money for what you get.

pmckeealaska

Well, I assume that with 6.5 hours to do, I'm paying mostly for labor. If I tried it, it would probably take 6.5 days

pmckeealaska

They also have a clock unit upgrade for $395 that sound more reasonable. Chris Johnson repsonded quickly to my concern about the cost of the level 1 mod. Below is his response:

Hi Chris,

Clock upgrades are very noticeable...and can be heard when using it as both a player and a transport.

If you need to keep it under $400, that's the way to go.....improved bass dynamics...and far better low level detail sonic parameters (soundstaging, ambience, hall effects).

==============================

Changing op amps, caps and resistors is also important...but, can only be done cheaply if you do the work yourself, and you only upgrade the parts quality to a certain level.

The op amp modules we use alone, are $55 retail each.....and we use 4 of them in our mod.


Thoughts? Doe this sound reasonable or is this BS?

ben62670

It's only around $150 for the caps resistors and OpAmps. Thats the way I would go.

pmckeealaska

Yes, but $150 for what quality Opamps, caps and resistors? Is there an appreciable sonic upgrade with the $55 OpAmps he's talking about?

And again, there's the issue of me even trying something like that. I found a 2900 service manual on ebay for $7. Would it be worth it to pick one up? Would it, along with the picks of the mods you've done from here allow me to do this upgrade myself?

pmckeealaska

Does anyone know how easy it is to replace the OpAmps in the 2900? If they can be pulled out and the replacements snapped in, then I might be interested in doing that. If they have to be soldered, then I probably won't want to do it.

billbillw

pmckeealaska wrote: »

Does anyone know how easy it is to replace the OpAmps in the 2900? If they can be pulled out and the replacements snapped in, then I might be interested in doing that. If they have to be soldered, then I probably won't want to do it.

Nearly all mainstream, unmodified (ie: original) consumer electronics equipment will have the opamps soldered in place. Socketed opamps are usually a mod that DIY (or tweak shops) install.

The problem we usually face is whether the opamps are through hole (easy to unsolder and replace) or surface mounted (not so easy for the average DIY'er to replace).

pmckeealaska

Does anyone have any good quality pictures of the power and audio boards for the denon 2900 with an explanation of what everything on the boards is? I'm looking to educate myself about knowing what an OpAmp, Capacitor, and other components are.

Plus, if I were to want to do some modding of this unit, where is a good place to buy components from. Thanks.

billbillw

I hate to say it, but I think you are on the verge of getting in over your head. It takes a fair bit of experience with electronics before you can start doing mods yourself. You have to be familiar with basic circuits, have at least basic soldering skills (and equipment), know how to order the correct parts, and have the ability to dis/re-assemble the units, which sometimes need significant work to get to the boards.

I didn't try my first mod until after years of learning and that was also with the help of a family member who is an experienced electronics technician.

Sometimes you need to just enjoy what you have; Otherwise, you need to spend money to get what you want in the form of professional mods or stepping up to better gear.

pmckeealaska

billbillw,

You are absolutely correct. because of this, I recently purchased a 2900 service manual and I bought a used 2900 on ebay for $25 that is in working order but used. I'm planning on teaching myself how to read schematics, learn about the important components in the unit (OpAmps, caps, etc) buy some of the needed equipment to do the mods, and using the poor used 2900 as my guinea pig. Once I feel confident about working on this kind of equipment, I'll proceed on my actual unit, but not until I feel confident in what I'm doing.

billbillw

pmckeealaska wrote: »

billbillw,

You are absolutely correct. because of this, I recently purchased a 2900 service manual and I bought a used 2900 on ebay for $25 that is in working order but used. I'm planning on teaching myself how to read schematics, learn about the important components in the unit (OpAmps, caps, etc) buy some of the needed equipment to do the mods, and using the poor used 2900 as my guinea pig. Once I feel confident about working on this kind of equipment, I'll proceed on my actual unit, but not until I feel confident in what I'm doing.

Oh man, I wish you would have said something before purchasing the service manual. It is easily found on the internet for free. A hint: Alway run a Google search for the model number + "service manual". You'd be surprised how service manuals you can find that way.

http://www.eserviceinfo.com/downloadsm/25689/Denon_DVD2900.html

Otherwise, sounds like you are taking a good approach with a test unit.

pmckeealaska

I tried downloading a manual from that site but for some reason I couldnt get it to work! At any rate, it only cost me $2.50 to buy the manual.

billbillw

pmckeealaska wrote: »

I tried downloading a manual from that site but for some reason I couldnt get it to work! At any rate, it only cost me $2.50 to buy the manual.

Well, that's not bad. The eserviceinfo site is tricky. Most of the manuals there are posted as multipart-RAR files. You need to download all parts of the RAR, then open the first file with WinRAR to re-assemble the archive.

pmckeealaska

Where is the best places to buy OpAMps, caps and the like? Does anyone have a preferred place to but these things on line. Since I'm going to start by practicing on a cheaper unit before trying anything on my own 2900, I'd like to buy components that are a little cheaper than what I might eventually out in my player once I feel ready to do so.

ben62670

The OPA-2134 is a good starter opamp for less than $10 each. Available at digikey.
http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx
You choose the adapter and add your choice of opamps. The 627 is the one George and H9 used.

WastelandWand'r

P-Alaska,
Not sure what shop you found, but I have had good luck in using Pyramid Audio on Fireweed in Anchorage. They use to distribute Denon and Carl, the service guy, was a breeze to work with. He was excited to see my 555II recently as he 'hadn't seen one in a while'. 120.00 later it was back up and running. Money well spent as I currently failed the electronics for dummies entrance exam at he local Community College.
Whatever path you choose, most importantly have fun with it.
My 3910 is tempermental when it comes to Rounder SACD's as mentioned previously.
Nathan