Restoring A Marantz Power Supply Board P800

[@chrischristov3914]

Hello young man, Th’s for your great videos. Do not worry, not boring at all. Actually it’s pleasure to watch and very helpful. You know sometimes we’re kind of scared to start, thinking too complicated but after watching you it’s kind of motivating and giving us confidence. Keep doing the good work 👍

[@jameshopkins7333]

I got a 2250b from an auction recently for $400 plus shipping. It had blown outputs in the left channel, my first tech job in 40 years. Rebuilt the power amp P700 and new on semi power transistors. Very satisfying. Dc out put was 18mv on the left and -70mv on the right, I adjusted them to the correct voltages. Going to start at the power supply and refurbish it. I also love Sansui and would love to see some video's of AH-Fix-it doing a Sansui, Restore a Sansui receiver or an integrated amplifier. Would be great! Thanks for the information. Must have watched the P700 video twenty times before i was confident enough to touch it.

[@psyclobe]

I really appreciate your videos; there's a lot of guides online but everyone else seems to take themselves too seriously. You are just an average guy mucking with electronics, this makes your content much more approachable.

[@cptsobczak]

Thank you for the video. I’m just getting started in this hobby and I appreciate any info you share. Nothing is boring, rather information that noobs like me are all ears. Cheers! and keep ‘‘em coming. I hope your channel continues to grow.

[@bigjeffliv]

These videos are outstanding and streets ahead of anything similar on this platform. You're clear, concise and methodical and I'm learning a lot about something I'm tackling myself. Thank you very much from the north east of England - you're playing a blinder, kidda! Keep it going!

[@MichaelYates]

Excellent work and very nicely done, look forward to the next installment.

[@laurgangilbert]

Another great video, Ive done a few of these myself, i prefer to heat that old glue then peel it off as I'm not thrilled about using acetone on a circuit board!

[@DuconLajoie101]

Thanks for the video, It helped me to better understand why my 2235b worked abnormaly and fix it. Good work !

[@java2architect]

Question - Why you didn't replace the resistors on the power board but only the semis and caps?

[@jeffstockton534]

Rapidly becoming my favorite subscription. Keep it up.

[@goncalodumas]

Your guides are a great learning asset. Thank you! I was just wondering how you pick modern components, how do you bridge old specs with new ones. That has been my greatest difficulty - soldering and swapping components are the easy tasks for me, selecting replacements to old devices is not.

[@AHFixIt]

That's a great question and something I debated including some commentary on in this video. I will probably make a video explaining this since it's something I've struggled with in the past as well since I'm just doing this as a hobby and have no formal education or training around this stuff. But to try to answer the question here, I'll say that capacitors are pretty easy - use same capacitance as original but feel free to increase the voltage to the next level if you want. Example, replacing a 10uf 35v cap with a 10uf 50v cap is totally fine. Regarding types of capacitors, I use three main types: Nichicon PW for power circuits and anything in a tuner board, Nichicon KA for signal path circuits where the capacitance is greater than 3.3uf, and WIMA film caps for signal path circuits where the capacitance is 3.3uf or below. Semiconductors get complicated and you need to be careful there. When I don't know what a replacement is, I just google it and 90% of the time someone has answered the question in an AudioKarma thread. So for the H811 diode, I just googled "1S2471 replacement" and saw that someone had recommended a 1N4148 diode. However, I say be careful because I've replaced transistors with something someone recommended and had voltages in the circuit get wacky. So always keep the original component around and intact until you've confirmed everything is working. When in total doubt, try to look up the datasheet for the original component and compare it to a new component. Also this is a fantastic resource and has worked well for me, but like I said, be careful: audiokarma.org/forums/index.php?threads/transistor-substitutions.688515/

[@cpgixxer]

It's the glue that causes the corrosion. The glue is used during manufacturing to hold the cap in place for shipping purposes. Common issue in these older units.

[@rugrataudio]

Great work and awesome video thanks!

[@jharp53]

Learning a lot from your videos. Thks ! Question, Rebuilding a 2252 800 board. Wanting to replace the DS131b and ds132b diodes. Are they the same diode? Saw your parts list and found your replacement for the ds131b (BY2Q8E-200E) Will that work for both of mine? Thanks for your help!!

[@dimitarkirchevdimitrov6321]

Excellent job mate and great vudeo👏

[@richardchuray329]

You didn’t mention anything about mounting the relay to the board. Did your replacement have the little stud attachment? The last one I replaced had the stud but the Omron MY2 didn’t have the stud. I had to hot glue it. Curious how you mounted yours

[@AHFixIt]

This one I just soldered to the board since it's board mount. The 2270 and probably 2245 use one with the stud and solder lug terminals, different part number vs the one used here. Those I just bend the outer terminals out for added mechanical strength and solder them.

[@mattiasthell822]

Thank you!

[@dlm504]

Hi I check the voltage at j804 and it is -34 volts how is that possible.

[@harlest71]

Hi, It says in you parts list that you used KSC945 for H803/H805. The only KSC945 that I'm finding uses EBC instead of ECB. Are you twisting the legs around? or is their a version of KSC945 that I can't find? Thanks

[@AHFixIt]

That's interesting. The datasheet on mouser is indeed showing EBC, but all my 945's in stock are ECB. They must have changed it. I bought mine years ago. In that case yeah just make the legs go where they need to go, put a piece of heat shrink over one leg if it needs to cross. When you receive the parts double check them for pinout

[@harlest71]

@@AHFixIt Thanks for the reply !!👍

[@jingdantes686]

Hi. Where can I get Nichicon capacitors? And also Im learning a lot from your videos. Very clear and straight forward.

[@AHFixIt]

Glad you're learning! I recommend buying them from mouser.com or digikey.com.

[@davesanders4381]

A minor correction on your parts list. The capacitor you listed for C807 should be a 10mfd @50v and you have it listed as 4.7mfd @50v

[@user-mv5bu2kk8b]

Replace all diodes

[@Managua-f1n]

You look like the actor that makes Capitan America.

[@jameshopkins7333]

Thankyou! . Been thinking that since day one.

[@waynepollard6879]

Show the work ! Not from 5 feet away and not in fast forward ! Thumb down .