CS-80 Question: 70 ohm Resistance Between+15V and GND
Forum rules
This forum follows the same rules outlined in Gear For Sale Rules and Guidelines
Moderators have the right to edit your posts to keep them within the framework of these rules.
This forum follows the same rules outlined in Gear For Sale Rules and Guidelines
Moderators have the right to edit your posts to keep them within the framework of these rules.
-
- Newbie
- Posts: 33
- Joined: Thu Mar 01, 2012 7:55 am
CS-80 Question: 70 ohm Resistance Between+15V and GND
With the power off, I'm getting a 70 ohm resistance between ground and the +15V card riser supply rail on a Yamaha CS-80 - does anyone know if this is this normal? Not sure if the decoupling capacitors on the new 4000-series sockets are contributing to this.
- synthRodriguez
- Supporting Member!
- Posts: 373
- Joined: Sat Apr 25, 2009 11:46 pm
- Real name: Scott
- Gear: Moog - Roland - Yamaha
- Location: Western Ohio
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
By the math that's 214 mA which sounds about right to me.
My CS-50 (with a couple of extra voice cards in it) pulls around 187 mA on the +15 rail when it's running, so a 214 mA value on a CS-80 with all the extra overhead would be a perfectly acceptable value I would think. I wouldn't give it another thought.
The caps shouldn't have anything to do with it regardless with a static measurement.
Scott
My CS-50 (with a couple of extra voice cards in it) pulls around 187 mA on the +15 rail when it's running, so a 214 mA value on a CS-80 with all the extra overhead would be a perfectly acceptable value I would think. I wouldn't give it another thought.
The caps shouldn't have anything to do with it regardless with a static measurement.
Scott
-
- Newbie
- Posts: 33
- Joined: Thu Mar 01, 2012 7:55 am
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
Thanks, Scott. The 500mA fuse blew on the power supply before I did all this testing, and a tech told me to check for shorts between the 15V rail and ground, hence my question. Need to make sure everything's safe before powering this thing up again.
- synthRodriguez
- Supporting Member!
- Posts: 373
- Joined: Sat Apr 25, 2009 11:46 pm
- Real name: Scott
- Gear: Moog - Roland - Yamaha
- Location: Western Ohio
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
Of course working load and unpowered resistance are two different things so there still could be a problem. Just saying it's not like it's a dead short or something, and at least it makes somewhat reasonable sense.
I get 187 ohm on the CS-50 from the ground rail to the +15 rail. Please let us know what you find.
I get 187 ohm on the CS-50 from the ground rail to the +15 rail. Please let us know what you find.
-
- Newbie
- Posts: 33
- Joined: Thu Mar 01, 2012 7:55 am
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
Am a little confused - are you getting 187 ohms or mA from ground to +15?synthRodriguez wrote:Of course working load and unpowered resistance are two different things so there still could be a problem. Just saying it's not like it's a dead short or something, and at least it makes somewhat reasonable sense.
I get 187 ohm on the CS-50 from the ground rail to the +15 rail. Please let us know what you find.
-
- Newbie
- Posts: 33
- Joined: Thu Mar 01, 2012 7:55 am
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
Well, I heard from another CS-80 owner, and he's getting 69 ohms from the +15V rail to Ground. Things are looking up!
-
- Newbie
- Posts: 33
- Joined: Thu Mar 01, 2012 7:55 am
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
Here are the resistances I'm getting between the power rails on my CS-80 and ground:
+15V = 70.3 Ohms
-15V = 64.5 Ohms
+8.5V = 337 Ohms
-6.5V = 878 Ohms
+10.6V = 540 Ohms
The rails can be accessed on the power supply just behind the output molex connector. The +15V is the brown wire at the top and they go down from there. I'm thinking my -6.5V could be low as a friend is getting 3.95 Kohms on his currently working unit, as well as 456 Ohms on the +8.5.
+15V = 70.3 Ohms
-15V = 64.5 Ohms
+8.5V = 337 Ohms
-6.5V = 878 Ohms
+10.6V = 540 Ohms
The rails can be accessed on the power supply just behind the output molex connector. The +15V is the brown wire at the top and they go down from there. I'm thinking my -6.5V could be low as a friend is getting 3.95 Kohms on his currently working unit, as well as 456 Ohms on the +8.5.
-
- Newbie
- Posts: 1
- Joined: Wed Apr 18, 2018 12:50 pm
- Contact:
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
With the power off, I am getting a 70 ohm resistance between +15V card riser rail and ground on my CS-80 - does anyone know if this is this normal?
- synthRodriguez
- Supporting Member!
- Posts: 373
- Joined: Sat Apr 25, 2009 11:46 pm
- Real name: Scott
- Gear: Moog - Roland - Yamaha
- Location: Western Ohio
Re: CS-80 Question: 70 ohm Resistance Between+15V and GND
CS-80 s/n 1274
Unpowered resistance readings at the power supply plug and current draw when operating.
==================
+15.0 __ 66.2 ohm __ 2.5 A
- 15.0 __ 65.6 ohm __ 2.4 A
+10.6 __ 532 ohm __ 674 mA
+ 8.5 __ 349 ohm __ 126 mA
- 6.5 __ 3.9 kohm __ 106 mA
Unpowered resistance readings at the power supply plug and current draw when operating.
==================
+15.0 __ 66.2 ohm __ 2.5 A
- 15.0 __ 65.6 ohm __ 2.4 A
+10.6 __ 532 ohm __ 674 mA
+ 8.5 __ 349 ohm __ 126 mA
- 6.5 __ 3.9 kohm __ 106 mA