Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
Pioneer SX 1250
I think I'd look for power supply problems, especially bad solder
connections and bad small capacitors in the regulated power supply area. The bias can be adjusted later, assuming it doesn't get really hot. I don't really think it's related to the shutting down problem. Mark Z. "Ross Mac" wrote in message ... Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross |
#2
|
|||
|
|||
Pioneer SX 1250
Try the obvious first. What condition is the heat sink compound in? If it's
dried out... replace the grease. Also... make sure the transistors are tight to the heat sink. Maybe... swap L for R speakers and see if the problem goes to the other side. Good luck... Ross Mac wrote: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross |
#3
|
|||
|
|||
Pioneer SX 1250
Subject: Pioneer SX 1250
From: "Ross Mac" Date: 9/15/03 8:12 PM Eastern Daylight Time Message-id: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross If it plays normally otherwise, I'd bet it's a bias problem. The carbon trimmers they use to set bias are pure garbage, and they'll drift just looking at them. There might be two adjustments per channel on this model. Flush them out with a quality cleaner, and see if they set up normally. If so, replace the pure garbage pots with mere crappy ones (one grade up and re adjust the bias. John Del Wolcott, CT "Nothing is so opportune for tyrants as a people tired of its liberty." Alan Keyes (remove S for email reply) |
#4
|
|||
|
|||
Pioneer SX 1250
I did check the supply and it is a good clean 65Volts. All the connections
also look great. Especially for a 25 year old amp. I will look some more today...thanks...Ross "Mark D. Zacharias" wrote in message ink.net... I don't know - Pioneers are NOTORIOUS for regulated power supply problems. The timing of his failure also suggests this to me. Mark Z. "John Del" wrote in message ... Subject: Pioneer SX 1250 From: "Ross Mac" Date: 9/15/03 8:12 PM Eastern Daylight Time Message-id: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross If it plays normally otherwise, I'd bet it's a bias problem. The carbon trimmers they use to set bias are pure garbage, and they'll drift just looking at them. There might be two adjustments per channel on this model. Flush them out with a quality cleaner, and see if they set up normally. If so, replace the pure garbage pots with mere crappy ones (one grade up and re adjust the bias. John Del Wolcott, CT "Nothing is so opportune for tyrants as a people tired of its liberty." Alan Keyes (remove S for email reply) |
#5
|
|||
|
|||
Pioneer SX 1250
I will go ahead and calibrate the stabilizer and power amp circuits today.
If the pots are bad I will catch it then. Thanks for all your help....Ross "John Del" wrote in message ... Subject: Pioneer SX 1250 From: "Ross Mac" Date: 9/15/03 8:12 PM Eastern Daylight Time Message-id: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross If it plays normally otherwise, I'd bet it's a bias problem. The carbon trimmers they use to set bias are pure garbage, and they'll drift just looking at them. There might be two adjustments per channel on this model. Flush them out with a quality cleaner, and see if they set up normally. If so, replace the pure garbage pots with mere crappy ones (one grade up and re adjust the bias. John Del Wolcott, CT "Nothing is so opportune for tyrants as a people tired of its liberty." Alan Keyes (remove S for email reply) |
#6
|
|||
|
|||
Pioneer SX 1250
There's lots more than just the 65 volts. Probably + and - 65, 45, 13, etc.
Mark Z. "Ross Mac" wrote in message ... I did check the supply and it is a good clean 65Volts. All the connections also look great. Especially for a 25 year old amp. I will look some more today...thanks...Ross "Mark D. Zacharias" wrote in message ink.net... I don't know - Pioneers are NOTORIOUS for regulated power supply problems. The timing of his failure also suggests this to me. Mark Z. "John Del" wrote in message ... Subject: Pioneer SX 1250 From: "Ross Mac" Date: 9/15/03 8:12 PM Eastern Daylight Time Message-id: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross If it plays normally otherwise, I'd bet it's a bias problem. The carbon trimmers they use to set bias are pure garbage, and they'll drift just looking at them. There might be two adjustments per channel on this model. Flush them out with a quality cleaner, and see if they set up normally. If so, replace the pure garbage pots with mere crappy ones (one grade up and re adjust the bias. John Del Wolcott, CT "Nothing is so opportune for tyrants as a people tired of its liberty." Alan Keyes (remove S for email reply) |
#7
|
|||
|
|||
Pioneer SX 1250
Looks like John had the correct answer...I found the bias trim pots to be
worthless garbage and almost unadjustable. I will replace today...I did calibrate them the best I could and the amp worked great all night....just ask the neighbors!!...hehehe....Thanks to all for your help! .....Ross "John Del" wrote in message ... Subject: Pioneer SX 1250 From: "Ross Mac" Date: 9/15/03 8:12 PM Eastern Daylight Time Message-id: Hi Folks, I have a Pioneer SX 1250 Reciever that is giving me problems. It shuts down after about 30 minutes and the right heatsink seems warmer than the left. I have the service manual and have run a few tests but thought I might ask around before I spend the next couple of days fighting this one......thanks for any help....Ross If it plays normally otherwise, I'd bet it's a bias problem. The carbon trimmers they use to set bias are pure garbage, and they'll drift just looking at them. There might be two adjustments per channel on this model. Flush them out with a quality cleaner, and see if they set up normally. If so, replace the pure garbage pots with mere crappy ones (one grade up and re adjust the bias. John Del Wolcott, CT "Nothing is so opportune for tyrants as a people tired of its liberty." Alan Keyes (remove S for email reply) |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Need help, please. Pioneer receiver VS. Lightning... | Electronics Repair | |||
Anyone have a source for Pioneer parts? (was: Pioneer VS. Lightning) | Electronics Repair | |||
Need Pioneer Service Remote GGF1381 | Electronics Repair | |||
Pioneer 60" Projection Tv | Electronics Repair |