Marantz SR5008 Protect Mode

[R_J]

Re: Marantz SR5008 Protect Mode

That seems low? one side of R3227 connects to 3.3v so something is pulling it low (cpu) or the resistor is open?
If any of the 3 protection lines were low, I would think the voltage on r3227 would still be more than 0.3v

What's the voltage on R3251 (it's a similar circuit)

[mmartell]

Re: Marantz SR5008 Protect Mode

UPDATE.. of sorts..

I pulled connector CP403 from the amp board which supplies the rail voltages and grounds and the unit started normally. I checked the protection history and it was still THERMAL B. After around 30 seconds I plugged the connector back in and heard a SNAP, the sound of something like a higher voltage cap discharging.

After that the unit starts up normally. Now that it's not in protection not sure how to troubleshoot it since the fault is no longer there.

[mmartell]

Re: Marantz SR5008 Protect Mode

That seems low? one side of R3227 connects to 3.3v so something is pulling it low or it's open?

Hmm.. you're right.. don't recall if I checked the other side of the resistor for 3.3v...

I know I measured it in circuit and it reads bang on 1k

[R_J]

Re: Marantz SR5008 Protect Mode

When you pulled that plug, the main caps were charged up, so when you pluged it back in it discharged the caps. through the amp outputs. not a good thing to do. If you disconnect that plug again make sure you discharge those two 10,000µf capacitors with a resistor an incandescent lamp could also work.

[mmartell]

Re: Marantz SR5008 Protect Mode

There is no access to those caps. Shouldn't they have a bleed resistor ?

More importantly, why did that clear the error and return the unit to a functioning condition ?

[mmartell]

Re: Marantz SR5008 Protect Mode

What's the voltage on R3251 (it's a similar circuit)

I wanted to take that measurement to compare it with R3227 until I found out it's on the bottom of the HDMI board.

[mmartell]

Re: Marantz SR5008 Protect Mode

Ok this unit has Gremlins.

If you google "marantz blinking led" or light or whatever you will see many people have problems with the protection circuit. There are also many who have noise in the speakers or popping or some channels playing too soft.

These issues are related.

If you hit the unit - yes hit it - at the right side towards the rear you can induce or reduce these symptoms. As for the protection issue it sometimes goes away from just moving the unit.

I've had this unit apart down to the main board and haven't found anything of note to cause these problems. I surmise that the edge connectors are to blame as they must be making intermittent contact due to thermal expansion and contraction.

In my case why would the Protection Bypass trick allow the unit to function correctly ? I can only imagine the SWM_3.3v line feeding the relevant cpu pins is getting sketchy at times.

Will have to look deeper when I get the chance. Thanks for the help R J.

[R_J]

Re: Marantz SR5008 Protect Mode

Very likley a bad connection somewhere, poke at various plug connections and components using a plastic or wooden stick, I have a couple chopsticks for this. It might be hard to locate but not imposible. An intermitint connection is likely tripping the protection, its just a matter of finding where it is. if it uses a double sided board it can even be a cracked feed through. imposible to see, so hard to find

[mmartell]

Re: Marantz SR5008 Protect Mode

The problem is it's full of edge connectors like pci slots and there are multiple slots per card. It's hard to isolate any one connector let alone a single pin of one connector.

[mmartell]

Re: Marantz SR5008 Protect Mode

I have this thing torn down. Found two joints torn from their solder pads, one on the MxPort card and one on a mounting tab of another card but that joint wasn't electrically connnected to anything anyhow.

The issue remains the same. Very difficult to isolate the problem because all cards are attached to each other - pushing on one essentially pushes on all.

Any ideas ?

[mmartell]

Re: Marantz SR5008 Protect Mode

The problem is definitely the edge connectors. I located three that were causing my problems.

I want to say it was the female part of the connector but I find it hard to believe these were not making full-time contact. I suppose the male pins could have been oxidized or something of the sort but they looked fine to me.

I resolved the issue by slightly bending the male pins within their sockets before replugging. The extra pressure helps make solid contact.

I would guess there's a manufacturing defect of some sort here. I tore this thing down and rebuilt it several times before isolating the problem and all the other edge connectors have held up fine.

[mmartell]

Re: Marantz SR5008 Protect Mode

Pic of one of the male connectors...

[JeffJ]

Re: Marantz SR5008 Protect Mode

Pic of one of the male connectors...

I know this is old by my unit just started doing the exact same thing do you recall what 3 edge connectors, i want to be least invasive as possible with pin bending.

[mmartell]

Re: Marantz SR5008 Protect Mode

I know this is old by my unit just started doing the exact same thing do you recall what 3 edge connectors, i want to be least invasive as possible with pin bending.

I still have this unit but have not plugged it in in some time. As for which connectors I don't recall except that one was the vertical board extending from the back plate.

There is something going on here for these to fail this way. You would be better served to find another way to make those contacts reliable again - I seem to remember my "fix" not holding up very well.

[JeffJ]

Re: Marantz SR5008 Protect Mode

I still have this unit but have not plugged it in in some time. As for which connectors I don't recall except that one was the vertical board extending from the back plate.

There is something going on here for these to fail this way. You would be better served to find another way to make those contacts reliable again - I seem to remember my "fix" not holding up very well.

Thanks for the input, the ol' tappy tap tap on the back right corner with a rubber handle of a Philips#2 fixes it first tap every time for about a week so its 100% something loose by thermal expansion and contraction.

I'll have a look. Thanks for narrowing it down for others.

I also see some users just disable the Protection circuit all to geather but thats a bit extreme for a loose connection.

[mmartell]

Re: Marantz SR5008 Protect Mode

Disabling the protection might stop it from shutting down but is not likely to cure the noise when it rears up.

Is yours making the odd speaker noises or just shutting down ?

[JeffJ]

Re: Marantz SR5008 Protect Mode

Disabling the protection might stop it from shutting down but is not likely to cure the noise when it rears up.

Is yours making the odd speaker noises or just shutting down ?

Just hitting a false thermal protection, No odd noise.

[JeffJ]

Re: Marantz SR5008 Protect Mode

Just wanted to update, the resolution to the random incorrect Thermal B error i was having was ultimately fixed by reflowing the main cpu (some of the pins looked cold) PN:R5F56108VNFP