marantz 4300 repair

[HAL9000]

I bought a 4300 quad-receiver in bad shape, although everything works there are a few problems. Rear L channel refused to work and stereo Fm is very slow.

I got it in original shape even the 2 inches of 70's dust was there..

nowadays we have memory for these kinds of things.

I started with power supply,

I replaced the main power transistors D313 and D331 with European BD243C (USA is TIP 4X) i wouldn't recommend replacing with original. D331 is very close to the limit build here. i replaced all the caps with panasonic (one JJ 1000µF)
i also repalced the keramic ones.. i don't like ceramic at all.

ooh yes and i replaced the 150Ω 5w resistor (was dirty and it smelled bad)

then i went to pre-amp and tone, i saw that masushita/national/panasonic/technics (purple caps) were their these thing are VERY BAD!!! allways replace these caps..

as you see here,ALL 25V 47µF where broken.

replaced all with panasonic FC
i removed some transistors in pre section. (repaired the non working channel)

FM
i put in new caps in the stereo decoding circuit, stereo works perfectly now.

Power amps.

these power amps are very powerfull. simmular to the 4400 ones.
4400: greater drives and some modifications in the bridge section.

finished

i tested the 4300 on my 8Ω dummyload.
it gave 160Watts before clipping.

very nice sound.

 

[BruceRPA]

WOW! Excellent post HAL9000! Very nicely done! :thmbsp: Good advice and excellent pictures too. I am sure that there will be more comments and questions. I will be following this thread with great interest. I also have a 4300 that works great but is otherwise unrestored. It's very nice to see a beautiful receiver like the 4300 get brought back to life and back it's original grand state.

From you avatar and the signature line below your user name, I think that "i like marantz!!!" is a bit of an understatement. I do agree. :yes:

 

[secondslc]

how hard is it to pull the boards from the quad receivers? Thats whats keeping me from doing mine, i always thought they were all wire wrapped in place, is it a simple de-solder?

 

[dr*audio]

Nice work!:thmbsp:

 

[Tmac83]

Nice work, looks great. How long did it take you to do the whole thing?

 

[HAL9000]

how hard is it to pull the boards from the quad receivers? Thats whats keeping me from doing mine, i always thought they were all wire wrapped in place, is it a simple de-solder?

You have easy acces to the power supply and main power-amps. just click this click that and you have your circuit in your hands! :thmbsp:

the pre-amp section is more difficult to get to.

I would recommend taking of the front plate.
losen all the bolds and screws of the TONE (bass treble mid) and the pre amp section 3 screws and one bold.

then you can easely get to you pre amp section see picture: 6
notice: after you finish recapping/repairing this section make sure you all the black wire are connected good!

wire raps are not that ''shitty'' to work with just work carefully

Tmac83: ± 4,5 hours ( i have all my components on stock)

 

[Oerets]

Hal9000 ,
Hello
Wow what a nice looking unit , nice that it cleaned up so well . Seeing how it turned out makes me want to over-haul something again . If you don't mind to much I have a few questions to ask .
What was wrong with the amp ?
Noticed you used FC's , do you like them better then the FM's ?
Also did you replace any of the original Polarized electro's with Non-Polarized in the signal path ?

Thanks for any info

Barney

 

[catrafter]

Nice work HAL!
A person could get a hernia flipping a 4300 over.

Tom

 

[HAL9000]

Hal9000 ,
Hello
Wow what a nice looking unit , nice that it cleaned up so well . Seeing how it turned out makes me want to over-haul something again . If you don't mind to much I have a few questions to ask .
What was wrong with the amp ?
Noticed you used FC's , do you like them better then the FM's ?
Also did you replace any of the original Polarized electro's with Non-Polarized in the signal path ?

Thanks for any info

Barney

Hi Barney,

ith the main amps was nothing special. Dc ws 0.0mV and bias was normal at 15mV

powersupply is usually in bad shape with these receivers. capacitors fail what will leed to transistor failure. I usually replace the 150Ω 3w resistor because it smels and 7W is better in long term use.

I youse panasonic FC en FM. the 220µF caps here are all FM the rest is FC
FC is very very good! but FM should be even better..
I notice when i play with a receiver(hard sof hard soft volume) power supply get really hot, with panasonic the power supply will preform much better with less heat forming!!!
is there are non polerized caps. i usuallt combine two polar one together.
-++- ESR will double.
:thmbsp:

 

[HAL9000]

Nice work HAL!
A person could get a hernia flipping a 4300 over.

Tom

lol, you never had a 2500
But all these machine are quiet heavey. and i like it that way..
have you seen those semi plastic marantz receiver build now..

SR 9600 top of the line weighs 12Kilos :thumbsdn:
marantz 4300 weighs 26.5Kilos :thmbsp:

 

[ruesselschorf]

how hard is it to pull the boards from the quad receivers? Thats whats keeping me from doing mine, i always thought they were all wire wrapped in place, is it a simple de-solder?

Yes, on 4300/4400 almost everything, even the Dolby circuit plugs in easily.
But the real master to service is the Marantz 4270, no plugs, no space at all everything crammed together, wire-wrapped with short wires. Ever replaced the speaker relays on a 4270?

Helmut

 

[Oerets]

Thanks for the great info HAL9000 , I too like the Panasonics . Wish they made the big ones in FC or FM's ..(10000uf 63V)

On the Non-Polarized Caps , I was thinking of changing the Polarized ones in the signal path to Non-Polarized and see if there are any improvements .
Have read that this will change the harmonics from odd to even . More like a tube unit will do .


Get much of a drift with the center indicator in warm up ?


Whats got the better sound between the two you think ?


Barney

 

[jstang]

I was wonder what Hal was up to.....

That 4300 was about dirty as one of my 4400's.... Any cat hair?

Very nice job as always....!

johnk

 

[HAL9000]

I was wonder what Hal was up to.....

That 4300 was about dirty as one of my 4400's.... Any cat hair?

Very nice job as always....!

johnk

no cat hair!!!! this time!!!

 

[HAL9000]

Yes, on 4300/4400 almost everything, even the Dolby circuit plugs in easily.
But the real master to service is the Marantz 4270, no plugs, no space at all everything crammed together, wire-wrapped with short wires. Ever replaced the speaker relays on a 4270?

Helmut

I have had 5 of these 4270. some good some really bad.
usually powersupply is dead. or one of the main amplifier are broken..

to give everyone an sneak preview....

power supply old (removed the transistors and some resistors too!!)

new (no panasonic)

 

[HAL9000]

Thanks for the great info HAL9000 , I too like the Panasonics . Wish they made the big ones in FC or FM's ..(10000uf 63V)

On the Non-Polarized Caps , I was thinking of changing the Polarized ones in the signal path to Non-Polarized and see if there are any improvements .
Have read that this will change the harmonics from odd to even . More like a tube unit will do .


Get much of a drift with the center indicator in warm up ?


Whats got the better sound between the two you think ?


Barney

The drift is usually caused by capacitors that fail the transistors in stabilizing the power supply circuit. But in these receiver stereo decoder is build discrete (without decoding chips) HA11XX MC120XX :thumbsdn: the capacitors here in the stereo decoder need to stabilize everything. if they are very slow (or non working) you get a drift of 100% no stabilization getting no stereo at all...

between witch is better?? 4300 4400?? before after refurbishment.
?

 

[ruesselschorf]

Get much of a drift with the center indicator in warm up ?


Whats got the better sound between the two you think ?


Barney

..basically, 4300 and 4400 have identically circuitry. So a4400 is a 4300 with a scope, and a slightly larger transformer for a few watts more from the same poweramps.
There should not be much difference sonically between good restored 4300 - 4400.

If your FM tuner drifts, do a complete tuner alignement according to SM first - sometimes this will cure the problem...

Helmut

 

[HAL9000]

..basically, 4300 and 4400 have identically circuitry. So a4400 is a 4300 with a scope, and a slightly larger transformer for a few watts more from the same poweramps.
There should not be much difference sonically between good restored 4300 - 4400.

If your FM tuner drifts, do a complete tuner alignement according to SM first - sometimes this will cure the problem...

Helmut

for a few watts more from the same poweramps.

no the 4400 uses different power transistors and different drivers.
also a lot of resistors are different.

i wouldn't recommend realigning the Fm tuner. unless you have a serious problem with it.
:thmbsp:

 

[ruesselschorf]

HAL9000:
no the 4400 uses different power transistors and different drivers.
also a lot of resistors are different.

That may be so. But from today's point of view that would make no difference, also transistor types vary with the year the unit was produced. You can swap the driver cards from 4400 to 4300 - no problem there....

Helmut

 

[HAL9000]

HAL9000:
no the 4400 uses different power transistors and different drivers.
also a lot of resistors are different.

That may be so. But from today's point of view that would make no difference, also transistor types vary with the year the unit was produced. You can swap the driver cards from 4400 to 4300 - no problem there....

Helmut

well,
i will keep the 4300 card in the 4300 :thmbsp:

jon