Kenwood DVR-505 will not power up

fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

Yes, I can come up with 5.6 vdc.

Do you suppose I should be able to disconnect the SMPS from the circuit and then feed the 5.6v in its place? The transistor Q201 also has to have a positive bias on its base to pull up the relay. I don't know if that positive voltage comes from the SMPS from what looks to be "R/C"

I am also wondering whether the 5.6vdc is sent out of the SMPS only when it does not sense a problem elsewhere in the receiver. I don't know what SMPS-CN4 does, but perhaps it carries the sensed information from other sections, such as the PAs. (??)

Thanks!

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

Thank you vtech! I appreciate the encouragement.

No, I'm not a dealer, I'm just a guy trying to fix my daughter's and her husband's receiver. I figure if I can get it fixed, they may invite her mother and me over for dinner some day (I'll probably have to bring a pizza or something).

Anyhow, thanks for the diagram! There is no chance you have the schematic for the SMPS, is there? I measured for voltage on perhaps 8 pins of the SMPS connector, because of JTS's comment, where values were shown on its pcb and none had voltage. Perhaps I could do a little more checking. Although, you are recommending I just replace that IC if I can find a replacement somewhere. And, of course, I know you have done that many times.

Where do you guys buy your service manuals and schematics?

And it seems that between your advice and JTS's, if I can get the relay pulled up, the receiver may work. In that case... why couldn't I just solder a strap across where the relay contacts are soldered? Bad idea?

Thank you for your time and expertise!

Frank

Justmanuals · Joined: 21 Aug 2004 Posts: 1948

Frank: I just sent you a complimentary copy of the parts and service manual.
and yes, it does include the schematics. Expect an email from yousendit.com

HtH
[email protected]
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fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

I couldn't find the 1M0380R IC anywhere but eBay... With shipping it comes to $20. It is in Malaysia and shipping time is 1 to 3 weeks. I imagine that means a month.

fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

WOW!!

Thanks Paul. I just downloaded the manual. And plan to go through it now.

What a great gesture!

What a great forum this is!

Many thanks.
Frank

Justmanuals · Joined: 21 Aug 2004 Posts: 1948

For anybody else who wants it, here is the link:

https://www.yousendit.com/transfer.php?action=download&ufid=bVlBT0NTTk01UjdIRGc9PQ

It will be valid for 2 weeks and/or 200 downloads.

Enjoy!

[email protected] Smile

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http://www.manuals4you.com

Need a manual now? Instant Download
http://www.justmanuals.com

fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

From looking at the block diagram of the Receiver, it appears the SMPS isn't designed to offer "protection". It is just sources(?) several low voltages for various points in the receiver. Unfortunately, neither a schematic nor a board layout of the SMPS is included in the service manual (go figure).

So, it would seem the next step is get the AC power relay picked up or bypassed and to order the 1M0380R switching IC from Malaysia via eBay.

Any other tips or ideas would be appreciated!

Thanks! You guys are a great team.

Frank

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

Like I mentioned, there was never any schematic for the SMPS and I do not have the one I drew some time ago. It was not meant to be repaired and no doubt there is no real protection. It is time consuming but you can try to draw your own if needed or even get the datasheet for the IC. (by the way it has a KA prefix).
Take a look at the block diagram to get a better picture of the entire unit. As you can see, the SMPS is primarily used as a standby source and relay driver and bypassing the relay will no doubt supply the txformer and start all other supplies but, the pulsating DC supply will still be there to disrupt. Technically you can use a substitute supply or even build your own separate supply.
As far as getting stuff from overseas, you just never know & it would probably take longer. Last time I got something from Ebay in Hong Kong, it took more than a month.

fpc3 · Joined: 02 Feb 2009 Posts: 31 Location: Shawnee, Kansas

Thanks vtech.

I understand now what you meant when you said you drew it out. Do you suppose if I put a strap across the relay contacts and just removed the SMPS, that the unit would work, but if it was turned off, there would be no turning it on with a remote?

However, it appears that it generates a number of voltages that may not be supplied from the primary source(?). It seems those voltages could be used "for dvd & video". 5v, 12v, 5.5v, 3.5v, 2.5v, -5v. I'll give it a shot. Without the schematic, I am having a hard time knowing if those voltages go into or out of the SMPS, although I think they come out of it.

The IC on the board that I have does not show the "KA" prefix. But I have seen some with that online. I did search on 1M0380R, and found that source on eBay, but like you say, that could take a month. But since you have replaced a bunch of them, I think it would be worth the gamble to buy one... two... perhaps and see if that has a positive effect.

The only other consideration, is like you mentioned, build my own power sources for the needed voltages. Not sure about the currents required by each.

Again, thanks for the advice and support!

If the house doesn't burn down, I'll let you know how it went.

Frank