Author Topic: DVD/TV/Media Player Box Player Modification (Read 7260 times)

rascal101 · « **on:** Jul 17, 2010 at 05:12 AM »

Would just like to share simple modifications I did with my LG DK130 DVD player.

The reason I did this is so I can maximize my DVD player both for watching movies and listening to audio.

The modification I did are as follows:

1. Placed Flashing Tape on the transport and Duct Tape on the top cover to reduce vibrations and improve low frequency response.

2. Replaced the RSM Output Coupling Capacitors to improve clarity.

Here are pictures of the DVD player

These are the tapes I've used

Here are the modifications on the transport and top cover

DVD transport

Top cover

Note: I am unable to use a thicker tape as this interferes with the DVD transport and push it downwards. In fact, there are indentions to the tape duct tape already after I screwed the top cover to the chassis.

The ff: shows the unmodified main board and the corresponding Integrated Circuit chips used

Zooming into the Operational Amplifier (op-amp) chip

Zooming into the Output Coupling Capacitors used (it is using RSM 22uF/16V capacitor; the brand is relatively unknown)

Below are the new Output Coupling Capacitors

Closer look

Showing the connections on the capacitors

Note: The Lelon and NCC capacitors are connected back to back configuration (so that it can be non-polar) with the Iskra and Mylar capacitor connected to the Lelon and NCC capacitors in parallel. hehe ... I may have to rewire the highlighted NCC cap (color brown) very soon as its - pin is connected to the + pin of the Lelon cap (color green). It should be + pin of the NCC cap connected to the + pin of the Lelon cap.

Thanks for looking

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rascal101 · « **Reply #1 on:** Jul 17, 2010 at 11:51 AM »

This afternoon, I'm placing heatsinks on the Audio/Video DAC and the Dual Op-Amp

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Onkyo606 · « **Reply #2 on:** Jul 17, 2010 at 07:51 PM »

ikaw talaga sir mell ang dami ng magandang nagiging resulta ng katikot mo congrats po

rascal101 · « **Reply #3 on:** Jul 17, 2010 at 08:47 PM »

Sayang naman kasi

Kahit simpleng player puwede ring umawit

Pandidoy · « **Reply #4 on:** Jul 17, 2010 at 09:06 PM »

Ayos Sir Mel

rascal101 · « **Reply #5 on:** Jul 18, 2010 at 09:32 PM »

Seems that it would be difficult to mount a heatsink on the Dual Op-amp (too small). Just focused on the Audio/Video DAC.

The thermal compound and heatsink

The heatsink mounted on the Audio/Video DAC

Another angle

rascal101 · « **Reply #6 on:** Jul 19, 2010 at 10:21 AM »

I've waited for 12hrs already and still the CDR king thermal compound does not "harden"

.

I miss the Loctite 384/7387 combo.

I wonder where can I buy this item cheaply

.

The Loctite 384 used to cost Php 1,400/bottle and the activator Loctite 7387 (for curing) used to cost Php 800.00.

rascal101 · « **Reply #7 on:** Jul 19, 2010 at 12:55 PM »

I secured the heatsink with polyester tape to the mainboard PCB. No choice.

I also replaced the NCC "KMA" with a Lelon SG 33uF/35V capacitor. It is a good thing I found one lying around. I thought I had already run out.

shainoy · « **Reply #8 on:** Jul 19, 2010 at 03:05 PM »

1. Placed Flashing Tape on the transport and Duct Tape on the top cover to reduce vibrations and improve low frequency response.

2. Replaced the RSM Output Coupling Capacitors to improve clarity.

1. How much improvement in terms of percentage?
2. Why the Heatsink for the DAC Chip? Sobrang init ba after the modification?

CeeV · « **Reply #9 on:** Jul 19, 2010 at 04:06 PM »

Query din sir..

Will it be same value of caps na pwede kong gamitin to modify my Platinum DV-999 DVD/videoke player?

And pls. share mo naman where could i source those materials..I knew how to solder and tinker a bit on Electronics but not knowledgable enough to decide on those values

rascal101 · « **Reply #10 on:** Jul 19, 2010 at 08:41 PM »

You can get the materials (eg capacitors) at Eleshop (Raon) located at Ronquillo Street.
Addendum: 7/20/2010
Note: The electrolytic, mylar and polypropelene capacitor are all there. It's very likely that they would not have the NCC KMA, Lelon SG capacitor or Iskra KNB2520 but what they have is good enough. If you like better capacitors you will have to check out RS Components or Farnell.

Better buy the non-polar capacitor so you do not need to place capacitors in back to back configuration. BTW, placing them in back to back configuration halves the total capacitance.

Ideally, you should use same value capacitors. However if this is not possible, you can use higher value capacitors although you should restrict yourself to within +/-5uF.

For a typical value of an output coupling capacitors for the DVD of 22uF, you can use from 17uF to 27uF or something very close to these values.

Why restrict to within +/-5uF of nominal?

When you increase or decrease the capacitors too much,

Increase
- Your low frequency response will improve but it will appear that the background noise or noise floor increases

Decrease
- Your low frequency response suffers and it will appear that the high frequency response is very "bright"

rascal101 · « **Reply #11 on:** Jul 19, 2010 at 08:53 PM »

Quote from: shainoy on Jul 19, 2010 at 03:05 PM

1. Placed Flashing Tape on the transport and Duct Tape on the top cover to reduce vibrations and improve low frequency response.

2. Replaced the RSM Output Coupling Capacitors to improve clarity.

1. How much improvement in terms of percentage?
2. Why the Heatsink for the DAC Chip? Sobrang init ba after the modification?

IMPROVEMENT

If I should use good, better and best as benchmarks, it is from good to better. If better capacitors or better layering of capacitors are used, it is from good to best.

HEATSINK

The Audio/Video DAC is operating within its specified operating temperature even when mods are done.

The reason I am placing a heatsink is this.

- Most modern DACs use what is called an internal band gap reference which produces a very accurate and stable reference voltage. With an accurate voltage reference, it would be easy for the DAC to generate the corresponding voltage (analog) to a binary or digital data input. Generally the slope or rate of change for the band gap reference voltage is least when it is close to 25degrees celsius ambient. By using a heatsink, we can hopefully make the Audio/Video DAC operate at a fairly stable temperature close to the 25degrees celsius ambient.

rascal101 · « **Reply #12 on:** Jul 19, 2010 at 10:00 PM »

Actually, a better mod would be to "clean" the power supply output via low ESR capacitor and a ferrite choke on the output wire harness. This will help the Audio/Video DAC more. However, this will be for later.

rascal101 · « **Reply #13 on:** Jul 20, 2010 at 06:23 AM »

I haven't really answered which is better, the non-polar or the polar electrolytic capacitor?

The answer to this is, the polar electrolytic capacitor.

The reason is, you have much more choices that have lower ESR than non-polar. However, this shouldn't stop you from using non-polar specially if space inside the DVD is a premium.

shainoy · « **Reply #14 on:** Jul 20, 2010 at 07:32 AM »

Sir, Thank you for sharing your project will try this out with a malfunctioning dvd player (tray) first.

rascal101 · « **Reply #15 on:** Jul 20, 2010 at 09:48 AM »

You're welcome

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odyopayl · « **Reply #16 on:** Jul 20, 2010 at 10:06 AM »

Quote from: rascal101 on Jul 19, 2010 at 10:21 AM

I've waited for 12hrs already and still the CDR king thermal compound does not "harden" .

I miss the Loctite 384/7387 combo.

I wonder where can I buy this item cheaply .

The Loctite 384 used to cost Php 1,400/bottle and the activator Loctite 7387 (for curing) used to cost Php 800.00.

Sir Rascal, it seems that CDR King Thermal compound is like a grease type and wont be hardened. You remember the classic heat paste compound we used on the metal transistors (white one)? for better heat transfer to heat sink?

rascal101 · « **Reply #17 on:** Jul 20, 2010 at 10:58 AM »

Silicone grease. Yes, I remember that one.

I was afraid that this might happen so I asked from CDR King then went to Deeco. Same answer. Titigas daw.
I took a chance. On the way home, I was even very careful so that the compound will not get exposed to the sun or heat.

Kakainis talaga

CeeV · « **Reply #18 on:** Jul 20, 2010 at 01:26 PM »

Sir thanks for a comprehensive reply..though medyo nose bleed na ko..hehehe

rascal101 · « **Reply #19 on:** Jul 20, 2010 at 01:35 PM »

Txt mo na lang ako pag mag mo mod ka na ng DVD player. I guide na lang kita step by step

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rascal101 · « **Reply #20 on:** Jan 17, 2011 at 06:47 PM »

I just wanted to share that I did some modification with the switched mode power supply on 2 of my Samsung DVD players:

1. Additional circuit to improve the tolerance of the current sense resistor
2. Additional circuit (at the bulk cap, Aux PVcc and output caps) to improve voltage tolerance
3. Addition of a differential filter choke

For the sound quality, I can just say that I will use similar technique on all my CD players ...

Next step, improve the tolerance on the feedback compensation circuit.

rascal101 · « **Reply #21 on:** Jan 17, 2011 at 07:19 PM »

By paralleling very large value resistor(s) on a resistor, the resulting value is approximately the same as the original.

To give you an example, say the current sense resistor is 1Kohm (in reality and in actual application, this is typically less than 1ohm) and you parallel the series combination of 2Kohm and 1Mega ohm. With all resistors at exactly 5%, the paralleling technique improves the tolerance from 5% to 4.995%. If you use 3 resistors in series instead of the earlier 2, you get more improvement - I leave the math to you.

As an example, I would like to suggest using say 100ohm then 800ohm then 24Kohm for the 3 resistors in series.

rascal101 · « **Reply #22 on:** Jan 17, 2011 at 07:43 PM »

As a general caution in electronics, it would be best if you familiarize yourself with switched mode power supplies or power supplies in general to avoid any untoward incident.

rascal101 · « **Reply #23 on:** Jun 11, 2016 at 04:32 PM »

2pcs approximation circuit being used in Android TV box