Marantz 2330B resurrection thread

[rpeter46]

My co-worker recently mentioned that he had some 'old' marantz gear lingering in his garage. He wanted to know if I was interested in buying. I told him "YES!" Bring it in, and we'll probably get a deal worked out. It was too heavy for him to lift, so I went to his house and brought home a 2330B and a Pioneer SX-950 for an entirely reasonable sum of money. He said there were issues with both.
The Marantz was his daily driver for years, and had already had some Output Transistors replaced(it was obvious). He said it quit powering on, and he took it to a tech. Local tech gave him a 'high estimate' to replace the front power switch, and my co-worker parked it.
I took it home and put it on my dim-bulb tester. After putting a fuse in the receiver(old one was missing), it just lights the bulb and doesn't seem to click the relay over at all.
1- I don't seem to find a schematic for this model available online(free).
2- there were no obvious signs of leaking/bulging caps, or other obviously char-broiled components. FIrst place to look? Main filter caps? Switch?(tested good continuity) Relay?

I would like to get this guy breathing and working well. I would like it to displace my Kenwood kr-9600 because of my concerns about an amp meltdown and NLA parts...

Thanks,
Paul

 

[rcs16]

Both nice receivers, hifiengine has both sx-950 & 2330B documentation, you need a login to retrieve.
for the 2330, ohm out the primary side,
Does it have the ac line voltage selector?, if so, make sure it is in the 120V position.
hook an ohmmeter across the ac plug and flick the power switch on, it should show some low resistance when engaged.
if it is open, check the line fuse (F001), the switch, ohm out the transformer primary windings.
If that is okay, then check all the the power supplies voltages, if not there check secondary fuses(FR01,02,03)do you hear the speaker protection relays engaging after 3-5 seconds after power up? lamps on?
that should be enough to get you going.

 

[KutzlerTrans]

Do the receiver lights even attempt to light??, if the answer is no, then you have a serious short.
You have a number of options.
Unplug the amps before firing up the dbt. If you still have a short, then check the rectifiers for shorts.
Does the transformer hum??? It should with a high current draw. You can start eliminating circuits right after the rectifier.
The big filters power your amp boards.
You can compare resistances of each filter against each other. Remember to take pictures and document all wire locations real good before disconecting and isolating stuff.

If unplugging the amps make the dial lights go on, then pull your output transistors and try it. If its still shorted, start pulling drivers and check for shorts working backwards through the amp, pulling stages until the dbt dims. Shorted transistors get resistors hot, so look for the heat source with a thermo gun. The heat will lead you to the draw.

I also have the same unit on a shelf with a dead nuts short. Someday ill get around to it, but for now, ill be interested in seeing what you find with yours.
Best wishes,
John

 

[rpeter46]

Both nice receivers, hifiengine has both sx-950 & 2330B documentation, you need a login to retrieve.
for the 2330, ohm out the primary side,
Answer: Primary side shows 3.0 Ohms
Does it have the ac line voltage selector?, if so, make sure it is in the 120V position.
hook an ohmmeter across the ac plug and flick the power switch on, it should show some low resistance when engaged.
Answer: Yes, shows 3.0 Ohms
if it is open, check the line fuse (F001), the switch, ohm out the transformer primary windings.
If that is okay, then check all the the power supplies voltages, if not there check secondary fuses(FR01,02,03)do you hear the speaker protection relays engaging after 3-5 seconds after power up?
Answer: No. Speaker relay does not click.
lamps on?
Answer: No lamps on.
that should be enough to get you going.

Thank you for the direction for the schematics. Here were the values I observed.

 

[rpeter46]

Do the receiver lights even attempt to light??, if the answer is no, then you have a serious short.
ANSWER: no lights present.
You have a number of options.
Unplug the amps before firing up the dbt. If you still have a short, then check the rectifiers for shorts.
Answer: After umplugging amp jumpers J016-18, DBT dims as it should and relay clicks!
Does the transformer hum???
ANSWER: YES-
It should with a high current draw. You can start eliminating circuits right after the rectifier.
The big filters power your amp boards.
You can compare resistances of each filter against each other. Remember to take pictures and document all wire locations real good before disconecting and isolating stuff.
ANSWER: Will do this next...

If unplugging the amps make the dial lights go on,
ANSWER: yes, dial lights are on now.
then pull your output transistors and try it.
RESPONSE: all of them at once? Or one at a time?
If its still shorted, start pulling drivers and check for shorts working backwards through the amp, pulling stages until the dbt dims. Shorted transistors get resistors hot, so look for the heat source with a thermo gun. The heat will lead you to the draw.

Thank you. This is good progress!
Paul

 

[rcs16]

So you also measure 3 ohms from the ac plug with the S001 closed?
Do you have a DBT (Dim bulb testers,100W lamp in series with the line) tester? If so good idea to have one and first test/power up with one. If it starts bright then goes dim you can assume that it okay to come off it.
Do the lamps lights come on?
Check all the power supply voltages, does the protection relay close?

 

[KutzlerTrans]

Yes, i am also interested in what the dbt is doing.
it should go bright, until the filters are charged and then dim down.
Your relay might not click with the dbt in use.

Ihave found that if the selector lights light (am/fm/aux/ ect.) Then its safe to go full power.
The main dial lights may still light with a short, so don't let that fool you.

If the selector lights do not light while on the dbt, Then i know i created a problem or its still shorted.

Unplugging the amps will split your choices of were to look first in your diagnostic path.

As you may know, your chassis is the ground (center winding) that you will be measuring voltages from.

 

[rpeter46]

Update: I tried only connecting one main amp channel at a time. Left channel(I believe) shows a dead short. DBT never dims. Right channel does dim the DBT somewhat, relay never clicks over, and a very tiny amount of smoke came from the direction of the output resistors(already been replaced by PO). Bad stuff going on in there... Do I pull one Output Transistor at a time to diagnose, or should I replace all of them at this point in the game?

 

[airtime]

This isn't going to help but I had to chime in.

I had both of those receivers and WOW, did you get a haul. Both are excellent. I was going to have my 2330b restored but life got in the way. A move or situation I've regretted to this day. And why I unloaded the Pioneer is any ones guess????

Best of luck

 

[rcs16]

It does not hurt to figure out what is blown, the amp will work with only one set of o/p pairs. So you have 4 pairs to use as your testers.
usually replace with similar types of pairs, do not mix and match different complementary pairs.
If the protection relay is not engaging then it is a DC offset issue(or other issue) that has to be figured out the source and then eliminate the problem,
Ohm out all the amp modules, comparing each other to figure out what is out of wack.

 

[KutzlerTrans]

I would pull all outputs out and try the dbt again. If it is dim, them you should be able to fire it up with full power.
Your relay should click.
Then make a chart of all the EBC voltages of the driver transistors back to the diff pair.
Then you will see exactly whats going on and if they coincide with the schematic values.
If the relay clicks and the values are good, then put a new set of outputs into it and re- try it with the Dbt.
Is the output transistor paste white or grey??

 

[rpeter46]

white output transistor paste

 

[rpeter46]

double post

 

[rpeter46]

I'm reading through this to learn how to test output transistors. No need to drag it out on here. I'll report back as soon as I get up to speed.

 

[rBuckner]

That is THE thread to learn this basic technique, glad you found it!