Marantz PM66SE

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
D

daveyboy11

Member
Joined 2007
Marantz PM-66 similiar to PM-57

Hi there. I am new to this forum and did start a thread regarding a fault on my Marantz PM-57 amplifier but was advised that the PM-66 had the same transformer and I could get some help from this thread. If anyone could help me with the schematic for that amplifier as I am trying to source a replacement transformer and need to know secondary voltages, VA etc. If anybody knew where I could actually get my hands on a replacement transformer I'd be eternally grateful. Many thanks for any help you might be able to give.
 
T

tynesider

Member
Joined 2008
My PM66SE AMP (10 years old) has a problem. While listening via a radio tuner the mute would sometimes cut in and out. It operated OK with a CD player. Then one day I switched on and the amp power lamp would not come on and the amp would not work at all. I found the fuse had gone in the power circuit and changed it and the amp worked again several times playing CD's, but the mute would sometimes cut in with a loud click. Now the fuse has blown again. Any ideas please?
 
C

Chudley

Member
Joined 2007
The mute you're referring to is the protection circuit activating, which could be for one of several reasons. The blown fuse would indicate a fair amount of current is being drawn by something within the amp. I'm far from an expert so cant really advise you on what steps to take, but I would probably start by checking for dry solder joints or cracks in the pcb/tracks near the power transistors on the heat sinks. There is a resistor which feeds the protection IC on this amp (R801 if I remember correctly), which runs VERY hot & eventually burns out - it happened on mine, and caused the protection to engage randomly until it died completely. If you look on the schematics you should be able to find it and test with a multimeter if you have one. Although this wouldnt cause the power fuse to blow as far as i know.

Good luck!
 
D

daveyboy11

Member
Joined 2007
Hi there. I posted a message asking where I could source a replacement transformer for my Marantz PM-57 amplifier but didn't get a response. If anyone could help me I'd really appreciate it as it is just sitting there broken and looking very sorry for itself.
Do i need to exactly match the secondary voltages? I don't seem to be able to find anywhere that has suitable transformers.
 
W

wojtek5001

Member
Joined 2005
something wrong with the schematic?

If D701 and D703 are normal silicon diodes (not-Shottky barier diodes), then Q703 (VAS CS) will dissipate above 0,3W just when amp is idle (no input signal). And 2SC2240 is a 0,3W transistor. And when outpit voltage will raise near clipping - twice amount of max power - so it surely die. :xeye:
 
S

spanfan

Member
Joined 2009
Ok thanks for replying anyway. I've got exactly the same fault. the resistors look ok but I can't see how to get at the bottom to ahve a go at the joints without dismantling the whole thing which I don't fancy doing.

Where did you get it repaired and was it expensive?
 
T

The Walrus

Member
Joined 2009
Idling current adjustment

Hello again. I have a little problem. My pm66se has a marked difference in loudness between the channels. So I tried to adjust semi-fixed resistors the way it is described in PM6010F service manual. In about 10 minutes after power-on my digital multometer shows 4mV idling current value on the left channel and 5mV on the right, but in the manual it said to be 10+/-2mV after more than 5 min.
If anybody has PM-66SE (74Pm66/15B) manual, please tell me that idling current setting value indicated in "idling current adjustment" section. Thank you.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom