JIM WILLIAMS need your help please

echo unit · 12th August 2005

Hello,

I am doing a little maintenance work on a Lexicon PCM 70.

I’m going to be changing all the capacitors in the Audio Input/Mix/Output & A/D convertor sections which are over 17 years old now.

The blue tantalum, Green Mylar, Black Electrolytic and Clear/Grey polystyrene/polypropylene ones are no problem. The Electrolytic Caps are teh ones that dry up the fastest but I think in this case, they are in the path of the Power supply and not the audio path...if this correct, will changing them affect the sound at all?

There are 2 grey polyester block capacitors They are labeled:

EVOX MMK 8731 .047uF

Should these be changed or left alone? Never seen anything quite like these anywhere else.

The 3 Low Pass Filters in the Convertor section are Integrated Circuits. should I leave them on the board. Do they wear like capacitors do or are they ok for life? I would like to change them if I can get the parts. They are labeled:

AFL 89WB 15250C5 MURATA D 70

Also, should the tiny green and blue ceramic capacitors should be changed for new ones too or are they fine?

Any help with these questions would be really great.

If you know where I can get a schematic of the PCM 70,I would really also appreciate that too.

Scinx · 13th August 2005

You'd increase your chances of help if you moved this to the geekslutz forum

echo unit · 16th August 2005

Jim...I'm picking up Klingons on the Radar...Can you give me an answer or at least beam me up there and explain some of this to me?

Jonkan · 16th August 2005

ask here: www.groupdiy.com

they can help you im sure.

In the Lab forum.

/J

12th August 2005	#1
echo unit Gear maniac Joined: May 2005 Location: Greenland Posts: 282 Thread Starter	JIM WILLIAMS need your help please Hello, I am doing a little maintenance work on a Lexicon PCM 70. I’m going to be changing all the capacitors in the Audio Input/Mix/Output & A/D convertor sections which are over 17 years old now. The blue tantalum, Green Mylar, Black Electrolytic and Clear/Grey polystyrene/polypropylene ones are no problem. The Electrolytic Caps are teh ones that dry up the fastest but I think in this case, they are in the path of the Power supply and not the audio path...if this correct, will changing them affect the sound at all? There are 2 grey polyester block capacitors They are labeled: EVOX MMK 8731 .047uF Should these be changed or left alone? Never seen anything quite like these anywhere else. The 3 Low Pass Filters in the Convertor section are Integrated Circuits. should I leave them on the board. Do they wear like capacitors do or are they ok for life? I would like to change them if I can get the parts. They are labeled: AFL 89WB 15250C5 MURATA D 70 Also, should the tiny green and blue ceramic capacitors should be changed for new ones too or are they fine? Any help with these questions would be really great. If you know where I can get a schematic of the PCM 70,I would really also appreciate that too.

13th August 2005	#2
Scinx Lives for gear Joined: Dec 2003 Location: USA Posts: 581	You'd increase your chances of help if you moved this to the geekslutz forum __________________ . Tak My latest project: For your listening pleasure or Listen via YouTube

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16th August 2005	#3
echo unit Gear maniac Joined: May 2005 Location: Greenland Posts: 282 Thread Starter	Jim...I'm picking up Klingons on the Radar...Can you give me an answer or at least beam me up there and explain some of this to me?

16th August 2005	#4
Jonkan Gear maniac Joined: Jul 2003 Location: Malmö, Sweden Posts: 241	ask here: www.groupdiy.com they can help you im sure. In the Lab forum. /J