Modding the Toshiba SD4960 DVD/DVD-A/CD/SACD player

elaubile · « **Reply #100 on:** 1 Jun 2005, 12:19 am »

Took a closer look at the unit this evening and discovered what the problem was. It turned out that it had nothing to do with the mods at all; my problems happened because the center channel speaker was turned off in the audio settings of the player. When I turned that speaker on, the sound was back to the way it should be

At least all of this was not in vain. A problem that I had noticed when I first changed all the capacitors was that a stable picture could not be maintained in "video component out" mode. While looking through all the capacitors on the board, I saw a dark substance coming out of a capacitor at ZE2. I changed it out and now the component video works great!

Thanks Bob for your help...

bigerik · « **Reply #101 on:** 1 Jun 2005, 03:10 am »

Hi All
Anyone in the Toronto area done the mods? Would you be willing to help out someone who is soldering challenged?

Erik

BobM · « **Reply #102 on:** 2 Jun 2005, 03:42 pm »

Well I can break the news now. Here's a link to an article I was contracted to write for IEE Spectrum magazine.

http://www.spectrum.ieee.org/WEBONLY/wonews/jun05/0605ngeek.html

It details the modification steps for the Toshiba 4960 and/or Samung 841 machines.

But anyone who has been following this thread already knows what's in the article.

Enjoy,
Bob

elaubile · « **Reply #103 on:** 7 Jun 2005, 06:23 pm »

Great article Bob, I wish I had read it before changing out almost all of the caps in my Sony STR-DE945 receiver. I should have obtained the schematic, found out which sets of caps to increase capacitance by 20% and which to leave at original values. I increased the capacitance of all caps and now I've got a nice big paperweight (something blew and smoked).

Woodsea · « **Reply #104 on:** 7 Jun 2005, 11:41 pm »

Bob,
Thank you very much. I should give this a try, now that I am working 1/2 time. If I smoke this thing though, my wife will never forgive me. I got into Audiophilia because computers were getting to expensive and I would manage to sizzle a processor or MB every 6 mos.
But I love to overclock, and this is kinda the same!
Thanks again for the great article. My 841 I hope will be that much better for it.
Eric

scott_m · « **Reply #105 on:** 4 Jul 2005, 04:19 pm »

After switching out all the recomended caps (not the video specifice ones), the imprement is pretty impressive. However I have two questions for anyone who has completed this (or perhaps has a better understanding of it than I do). One, what is the purpose of the bypass coupling caps - are they necessary with the 1 u sonicaps and, if they are, how are they wired? Second, having left the bypass coupling caps out of the signal, the new rca jacks sound good, but not as good as the original audio out Jacks on the dvd player. I thought by removing the two caps after the dac chip I was hi-jacking the signal - how is it still getting to the original rca jacks?

Just curious. And thanks!

Scott.

BobM · « **Reply #106 on:** 4 Jul 2005, 10:10 pm »

By taking the two caps out and "hijacking" the signal to the coupling caps you are effectively dismantling the 2-channel signal path. But you will still get a signal out of the multichannel path. Check your setup menu options and make sure that the multichannel has the back and center speakers turned off and the two front speakers set to "large", so you get the whole thing.

Yes, the multichannel RCA's will sound better then before, since you beefed up the power supply and digital signal processing caps. It's a matter of taste whether you like the op-amp multichannel output or the coupling caps better. If you like the op-amps then I suggest improving the caps around the front channel op-amps (use the small BlackGates if you can).

As for bypassing the coupling caps, no it's not necessary, but I found it adventagous in my system, and since it only cost another $4 for two .1uF Sonicap II's I felt it was a worthwhile addition. YMMV

Enjoy,
Bob

spins · « **Reply #107 on:** 6 Jul 2005, 12:15 pm »

Anyone know if the Toshiba/Samsung Mod that works for the HD-841 will work for the Samsung HD-941?

Thanks

BobM · « **Reply #108 on:** 6 Jul 2005, 01:31 pm »

Possibly, but I would suggest getting the schematic for it and identifying the parts for replacement before you begin. You can also research the digital chip (is it the same one or not?) and see if you can do a coupling cap output on it, or if you're stuck with the op-amps.

Enjoy,
Bob

scott_m · « **Reply #109 on:** 7 Jul 2005, 07:33 pm »

Regarding the 'x' rated caps - is there a positive and negative I need to pay attention to when replacing them with the auricaps?? I couldn't find any indication on the replaced caps themselves or on the circuit board.

Bob M - by the way, I hooked up the modded toshiba (pre - diode and 'x' rated cap replacement) to a higher quality tube amplifier and and now I prefer the non-opamp rca outs.

Thanks in advance,

Scott.

BobM · « **Reply #110 on:** 8 Jul 2005, 12:39 pm »

Scott M,

Yes, there is a "correct' orientation on the Auricaps. Take a look at the modded photo on the 2nd page of this thread and you will see how they are aligned (Red wire closest to the chassis side).

Glad to know it's working well for you.

Bob

scott_m · « **Reply #111 on:** 8 Jul 2005, 04:37 pm »

How do you tell which leg is positive and which negative? And, which of those coresponds to the striped end of the original diode which is being replaced? As always, thanks very much in advance.

Scott.

Eastwood · « **Reply #112 on:** 15 Jul 2005, 02:43 pm »

BobM,

First let me thank you for your description/detail in modifying the 4960/841 (I bought the 841 from OneCall for $90). I can not wait to burn mine in a take it for a test drive.

I have made it nearly all the way thru the modification you describe in the IEEE Spectrum article...but have a couple questions for you (hope you do not mind).

1. I am making the Swenson mod on all audio channels...both for CD and for SACD,DVD-A. So I removed all the old RCA connectors and installed new individual ones. My first question lies in the coupling caps. I know the coupling 1 uF Sonicaps tap off the D/A output, but could you clarify the purpose and location of the 0.01 uF Sonicap IIs? I know the Silver Mica bridging caps go across the RCA + and - for noise if needed. Not sure where the 0.01 uF bypass caps hook up. Is there a pic somewhere on it?

2. Just to let you know the VE6,7 100 uF capacitors voltage rating in my 841 unit is 16V not 10V as listed in the article.

Any help you can provide is greatly appreciated!!!

rhale64 · « **Reply #113 on:** 14 Aug 2005, 06:30 am »

Bob I would also like to thank you for your patience. Anyway I have a few-hundred questions for you.

I have bought the 4960.I am going to be putting all my internals into an older Toshiba 4700 box. I will have plenty of room in there for anything including the Super-Clock, I hope. The transport will be up higher and since the drawer location would be higher I can put in a lot of shock protection. Anyway, I am a total newb. I would like to know the location numbers on the board for the op-amps. And if you could, the cap locations that would need replaceing if I changed it out. Also on my old 4700 the rca hookups are in different places from the 4960, of course. I was wondering if the right way to do this, if I change the opamps, is to just unsolder the jumpers going to the rcas and throw them away. Then put in new tiffany style with grommets on both sides of back plate as your instructions. Then resolder wire to the ground and hot locations on the board. Am I right in this? Also what gauge and type of wire should I use? I am going to probably change out the jumpers on the board. Wire in an IEC with a star ground configuration. And just get some kind of points. Also line the cabinet and transport. But this is going to be an extremely slow process. I would sure appreciate all help I could get.

goldlizsts · « **Reply #114 on:** 14 Aug 2005, 01:34 pm »

Hi,

I am trying to mod the Samsung HD841, same as the Toshiba 4960. I've taken the circuit board and the new parts for the power supply sectin out, and plugged in my solder to begin to work. I somehow could not desolder the caps, believe it or not. I set the Solomon 976 ceramic solder (50-watt) to around 300C already, still couldn't do it. I am using Radio Shack desolder braid also. I thought the solder gun was malfunctioning, so I tried it on the WBT 4% silver solder I just got, low 180C or so melting temperature, and it melted right away. So, it's not likely my solder gun is not hot enough. What would it take to desolder the damn Samsung solder area? May be their solder is much higher temperature rated? Thanks.

goldlizsts · « **Reply #115 on:** 16 Aug 2005, 01:11 am »

Hi,

I read BobM's posting of his Toshiba SD4960 mod. I'm doing the Samsung HD841 mod, which is essentially the same machine. I have desoldered the first few power caps. In the HD841's case, the PER10 cap (Digikey part #P6849-ND) is much larger than the replaced cap. I wonder if you had the same situation, that the new cap would not fit in the slot. Did you do what I'm thinking, solder a pair of extension wires, and place the new cap other than vertical, just let it lie sideways? Much appreciated. The other replacement caps I think I will not have any problem with, but just this 180uf400V is the problem. Thanks.

scott_m · « **Reply #116 on:** 16 Aug 2005, 03:29 am »

I think I did end up extending one of the legs on that large cap. I know I ended up having to bend the body of the cd player slightly (it was okay, because the shell piece that fits over the top covered it up nicely) so that I could fit the circuit board back into the case.

Scott.

BobM · « **Reply #117 on:** 16 Aug 2005, 12:53 pm »

Rhale,

Given the different path you are taking with the mod - replacing op-amps, I would strongly suggest that you pick up the Samsung HD841 Service Manual. All of the schematics are included and you will definitely need them to trace outthe signal paths and part numbers.

Good luck,
Bob

BobM · « **Reply #118 on:** 16 Aug 2005, 12:59 pm »

Goldlizsts,

Don't know why you can't desolder the parts. You may have to go hotter, but get an alligator clip to dissipate the heat between the solder and the body of the part. I use a pair of forcepts for my soldering, to both hold the part and dissipate the heat.

Another method I find works well is to just apply heat to the join and wiggle the part back and forth until it comes out. You'll have to go back and forth between the 2 legs a couple of times. Then use a straignt pin with some heat on it to punch through the leftover solder and get the hole back.

As for parts sizes, yes that first big cap is big. I applied some Moretite to the bottom of it and it actually sits on top of a diode or a resistor. If you're replacing the diodes as I suggest you will have to mount one of them under the board. Make sure you insulate it well so it doesn't short against the case or a trace.

You will also have trouble with one other set of caps in the power supply section. I had to sit one on top of all the others, putting some thin shrink wrap on the legs. There's a picture of it in an earlier post.

Good luck,
Bob

rhale64 · « **Reply #119 on:** 17 Aug 2005, 12:38 am »

Quote from: BobM

Rhale,

Given the different path you are taking with the mod - replacing op-amps, I would strongly suggest that you pick up the Samsung HD841 Service Manual. All of the schematics are included and you will definitely need them to trace outthe signal paths and part numbers.

Good luck,
Bob

Bob would replacing the op amps yield the same result or be better or worse than the Swenson mod? I have a very liquid taste in music. I want a non grainy midrange with a rythmic sound. I want it to make me want to get up and dance.
Also I noticed in your reply to somebody about which caps to swap for Black Gates. I cant find any 47uf 16 volt blackgate caps n or nx series. There is however some of your original swap 100uf 16 volt. There is some stantard and FK series. Is there good alternatives? Why does everyone use electrolitic caps instead of any other types? IE: poly, oil in film etc; As you can tell I am a novice.
Also what about replacing resistors. I know in crossovers they are important. What about digital source components?