Looks like I fixed the problem with the Sony STR SE501 Stereo Unit. The problem was cracked/cold solder joints on the Main Board. Removing the Main Board, I inspected the bottom for cracked or cold solder joints which would cause the intermittent signal loss/relays going off. Sure enough, there were approximately 12 cracked/cold solder joints. The problem areas were the relay solder connections to the Main Board -and- the RCA jack connections to the Main Board. On mine, only one side/row of solder joints were cracked on both the relays and the RCA connections. Therefore, I oly soldered the ones that were apparently cracked. Here are some suggestions on the repair. If you don't know how to solder, you may want to have it repaired for you but I found it wasn't that bad. Took about 1/2 hour to repair. Un plug unit from wall voltage. 1) Remove all black screws from sides and back of case. 2) Slide black cover back first about one inch and then up (front edge is held down by slide-in tabs from front panel). 3) You will see the Main Board on bottom, a Video Board and DVD Board attached to the back panel (indicated by the yellow and orange RCA Jacks). The DVD (Orange) board stays with the Main Board during removal due to a white plastic standoff which is too troublesome to remove. 4) Remove three gold screws holding down main board. Remove four gold screws holding down silver metal large waffle-like heat sink (note heat sink screws are shorter than all other gold screws). 5) CAREFULLY unplug with slight pull/jiggle the ribbon cables going to the main board and Video and DVD boards. Note: the beige/brown plug ribbon connections on the main board should be left alone (remove the cable from the opposite end, usualy a different board. Some of these ribbon cables come from the front panel area and some from the power supply area. Another comes form the antenna Coax area (be very careful not to bend this one to much as it is fragile). 6) Remove all gold screws from rear panel of unit with the exception of the Coax antenna input module (that can stay attached to back panel) AND the video (yellow) and S-Video modules. 7) Slide power cord holder from back panel cutout. 8) Remove back panel (Video and S-Video boards still attached to back panel). 9) Remove Main Board (DVD board still attached) 10) Using a high power magnifying glass, inspect solder joints on underside of Main Board - pay particular attention to the underside connections of the BLUE relays (RY730, RY740, RY601, RY550, RY560) -AND- the solder joints for the RCA connectors near the back edge of board. Cold/Cracked solder joints may appear as a very slight circle or "crack" line halfway up the solder bubble from which the soldered-in pin protrudes. After a few minutes of inspecting the good solder joints, you should easily be able to spot any bad ones. Inspect the entire board for the cracked solder joints (my guess is the relays and rca connections are the primary touble spots). 11) Farm this task out if you can't solder but not having soldered in a few years - I was able to do it relatively easily taking care not to bridge any PC board connections that were not meant to be bridged (which means you need very very little solder to just touch up the joint - less is more in this scenario). SOLDER the cracked joints with a fine tip soldering iron and electronic solder (from radio shack). Just give the cracked joint a slight touch of heat and solder to cover the crack. It may not look as pretty a the factory job but it should work. 12) Inspect each area you soldered to ensure you did not use too much and bridge any pcb connections. Scrape off any slight solder veins which may have bridged. 13) Reassemble taking care to press straight down on ribbon cable connections.Be especially careful with the RF antenna ribbon/flat cable as it bends easily. (Don't force, inspect any connection pins you suspect may have gotten bent at removal). 14) Test unit. Like I said, this process too about 1/2 hour and was fairly easy. Just make sure to use the correct tools to do the job. Good light, magnifying glass, fine tip soldering iron, decent solder, and careful dissasembly. Good luck - I hope this helps.

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