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| "David Farber" <farberbear.unspam@aol.com>: Jun 15 05:27PM -0700 The pc board is from a Korg piano. The model number is C-56M. Schematic is here. http://www.synfo.nl/servicemanuals/Korg/CONCERT-26-56M_SERVICE_MANUAL.pdf The relevant pages of the service manual are page 30 for the pc board view and page 121 for the schematic. Photo of the board I'm fixing is here. http://webpages.charter.net/mrfixiter/images/Electronics/Korg/KLM-1653-pc-board.jpg The problem is that all of the 10uF 10v caps are bad. I've removed them and replaced them with through-hole capacitors. Due to the damage caused by the leaking electrolyte, I was forced to be creative in finding working paths in the circuit that were still usable. There is one spot I got stuck. Looking at the photo, you will see a 5 pin connector which connects the volume control on the top of the piano to this circuit board. There is no continuity between the left and right output caps to the connector. I've made a trail of red dots in the photo where the connections are supposed to be. The dots do not represent a specific physical path but are there for clarity. The way the signal path connects to the two pins are from the negative sides of C116 and C117. (page 121 in the service manual) and then through the two through-hole connections adjacent to the capacitors. Is it possible to solder jumper wires from the capacitors to the through-hole connectors (highlighted by arrows)? Thanks for your reply. -- David Farber Los Osos, CA |
| mike <ham789@netzero.net>: Jun 15 09:04PM -0700 On 6/15/2015 5:27 PM, David Farber wrote: > possible to solder jumper wires from the capacitors to the through-hole > connectors (highlighted by arrows)? > Thanks for your reply. Why can't you just run the wire from the cap to the connector? |
| "David Farber" <farberbear.unspam@aol.com>: Jun 15 09:55PM -0700 mike wrote: >> capacitors to the through-hole connectors (highlighted by arrows)? Thanks >> for your reply. > Why can't you just run the wire from the cap to the connector? Hi Mike, I wanted to avoid running wires from the top of the board to the bottom. If you meant running wires directly to the connector, those terminals are used when the cable from the volume control gets plugged in. If you meant anything else, I'm not sure what you meant. :-) Thanks for your reply. -- David Farber Los Osos, CA |
| N_Cook <diverse@tcp.co.uk>: Jun 16 08:03AM +0100 On 16/06/2015 05:55, David Farber wrote: > when the cable from the volume control gets plugged in. If you meant > anything else, I'm not sure what you meant. :-) > Thanks for your reply. so drill a hole through a blank part of the pcb to pass the jumper wire |
| "Gareth Magennis" <sound.service@btconnect.com>: Jun 16 09:03AM +0100 "David Farber" wrote in message news:mlnqes$ph8$1@dont-email.me... The pc board is from a Korg piano. The model number is C-56M. Schematic is here. http://www.synfo.nl/servicemanuals/Korg/CONCERT-26-56M_SERVICE_MANUAL.pdf The relevant pages of the service manual are page 30 for the pc board view and page 121 for the schematic. Photo of the board I'm fixing is here. http://webpages.charter.net/mrfixiter/images/Electronics/Korg/KLM-1653-pc-board.jpg The problem is that all of the 10uF 10v caps are bad. I've removed them and replaced them with through-hole capacitors. Due to the damage caused by the leaking electrolyte, I was forced to be creative in finding working paths in the circuit that were still usable. There is one spot I got stuck. Looking at the photo, you will see a 5 pin connector which connects the volume control on the top of the piano to this circuit board. There is no continuity between the left and right output caps to the connector. I've made a trail of red dots in the photo where the connections are supposed to be. The dots do not represent a specific physical path but are there for clarity. The way the signal path connects to the two pins are from the negative sides of C116 and C117. (page 121 in the service manual) and then through the two through-hole connections adjacent to the capacitors. Is it possible to solder jumper wires from the capacitors to the through-hole connectors (highlighted by arrows)? Thanks for your reply. -- David Farber Los Osos, CA You could prize off the plastic connector housing off the pins, and solder thin wires from that to the capacitors, then put it back again. Gareth. |
| "David Farber" <farberbear.unspam@aol.com>: Jun 16 07:30AM -0700 Gareth Magennis wrote: > possible to solder jumper wires from the capacitors to the > through-hole connectors (highlighted by arrows)? > Thanks for your reply. You could prize off the plastic connector housing off the pins, and solder thin wires from that to the capacitors, then put it back again. Gareth. Hi Gareth, Good suggestion but I was still wondering if a wire can be soldered to those circular through-hole connectors. Thanks for your reply. -- David Farber Los Osos, CA |
| "Gareth Magennis" <sound.service@btconnect.com>: Jun 16 05:41PM +0100 "David Farber" wrote in message news:mlpbu6$vq9$1@dont-email.me... Gareth Magennis wrote: > possible to solder jumper wires from the capacitors to the > through-hole connectors (highlighted by arrows)? > Thanks for your reply. You could prize off the plastic connector housing off the pins, and solder thin wires from that to the capacitors, then put it back again. Gareth. Hi Gareth, Good suggestion but I was still wondering if a wire can be soldered to those circular through-hole connectors. Thanks for your reply. -- David Farber Los Osos, CA Dunno, sometimes these vias are very small, and/or covered in solder resist. You could always drill them a bit bigger, bearing in mind they will no longer connect both sides. Gareth. |
| John Robertson <spam@flippers.com>: Jun 16 10:47AM -0700 On 06/16/2015 12:03 AM, N_Cook wrote: >>>> damage caused by the leaking electrolyte, I was forced to be >>>> creative in finding working paths in the circuit that were still >>>> usable. There is one spot I got stuck. Looking at the photo, you ... Is it possible to solder jumper wires from the >> anything else, I'm not sure what you meant. :-) >> Thanks for your reply. > so drill a hole through a blank part of the pcb to pass the jumper wire Multi-layer board - you have no idea where the traces are running so drilling a hole is not be a good idea, unless the board is translucent enough that you can see the inner layers that is. John :-#(# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| John Robertson <spam@flippers.com>: Jun 16 10:49AM -0700 On 06/16/2015 9:41 AM, Gareth Magennis wrote: > those > circular through-hole connectors. > Thanks for your reply. Multilayer board, vias may connect to other traces in other layers that the top and bottom alone. Mind you if it is just a four layer board then the two middle layers are typically power and common (but not always). John :-#(# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| "Gareth Magennis" <sound.service@btconnect.com>: Jun 16 07:50PM +0100 "John Robertson" wrote in message news:DKadnQB4qfud_x3InZ2dnUU7-fednZ2d@giganews.com... On 06/16/2015 9:41 AM, Gareth Magennis wrote: > those > circular through-hole connectors. > Thanks for your reply. Multilayer board, vias may connect to other traces in other layers that the top and bottom alone. Mind you if it is just a four layer board then the two middle layers are typically power and common (but not always). John :-#(# I suspect this is a dual layer PCB. Gareth. |
| "hrhofmann@sbcglobal.net" <hrhofmann@sbcglobal.net>: Jun 15 08:59PM -0700 I put a 1,000 (1K) ohm resistor across each battery. The voltage stayed at 5.85 volts for 3 of the 4 batteries, the 4th battery went down to 5.2 volts. SO 3 out of 4 supported a 5.8ma load with no change in output voltage. Impressive!!! |
| ggherold@gmail.com: Jun 15 11:26AM -0700 On Thursday, June 11, 2015 at 12:00:30 AM UTC-4, Trevor Wilson wrote: > The last three are not deal-breakers though. I've seen a few on eBay, > but am not certain about quality. Like this: > http://www.ebay.com.au/itm/Dr-Meter-HY5005E-2-SWITCHING-DUAL-DC-POWER-SUPPLY-50V-5A-Variable-/221422197471?pt=LH_DefaultDomain_0&hash=item338dca9adf I think there is one place in China making all those and re-branding them. We buy them from Mastek. http://www.mastechpowersupply.com/ The ones we get now say Volteq on the label. George H. |
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