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1250 recap question

B

bdblkta

Well-Known Member
I am in the process of recapping my 1250. Currently I have the amp boards out and have only the two large caps on each board (C15 & C16) left to complete them; however I have a few questions.

1. The original 470/80 caps had 3 leads while the replacements UHE2A471MHD 470/100 only has 2 leads. Did I order the wrong parts or do you not need the third lead?
2. The capacitor in C11 is the tiny little guy that looks like a water drop and is being replaced with ECQ-E2224KF .22uf 250v but I’m not sure which lead is positive. Do I need to orient the text facing the same direction as the original?

So far things have been going well. I have completed the 4 removable boards with the exception of these 4 caps and will do another board this evening. I also would like to tell everyone who wants to here about it that the radio shack solder sucker is an excellent tool for this job and being only $11 it is a great value.

Thanks for any help, Josh
 
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Hi,
It has been awhile since I recapped my SX-1250 but here is some advice.
The third lead on your old caps is only for support on the board. Don't worry about it. It has no other function.
The capacitor in C11 is a tantalum capacitor. The film capacitor you are using to replace it has no polarity so it doesn't matter which way you put it in. I am curious why you chose EC-E2224KF as the replacement. Panasonic has another film capacitor ECQ-V1H223JL (0.22/50V) that is closer to the original value.
As a general rule you should replace all tantalum capacitors and with values of 1uF or lower it makes sense to use poly film capacitors. When you do this polarity is not an issue.
Good luck
 
bisonguy said:
Hi,
It has been awhile since I recapped my SX-1250 but here is some advice.
The third lead on your old caps is only for support on the board. Don't worry about it. It has no other function.
The capacitor in C11 is a tantalum capacitor. The film capacitor you are using to replace it has no polarity so it doesn't matter which way you put it in. I am curious why you chose EC-E2224KF as the replacement. Panasonic has another film capacitor ECQ-V1H223JL (0.22/50V) that is closer to the original value.
As a general rule you should replace all tantalum capacitors and with values of 1uF or lower it makes sense to use poly film capacitors. When you do this polarity is not an issue.
Good luck
Click to expand...

Excellent answer, well covered, couldn't have said it better myself. (the question however...)

The choice of ECQ-E2224KF that I made had to do with what was left in stock at mouser at the time, with the objective of getting everything in one order at the same time. Simply - that's all that was left AT THE TIME, they have since gotten restocked (in several different manufacturers) with the lower voltages.... :D
 
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bisonguy said:
I am curious why you chose EC-E2224KF as the replacement. Panasonic has another film capacitor ECQ-V1H223JL (0.22/50V) that is closer to the original value.
As a general rule you should replace all tantalum capacitors and with values of 1uF or lower it makes sense to use poly film capacitors. When you do this polarity is not an issue.
Good luck
Click to expand...

I used the latest list in the thread that Kingbubba had created for the BOM through mouser and this is the cap specified. Should I reorder the the lower voltage caps?
 
bdblkta said:
I used the latest list in the thread that Kingbubba had created for the BOM through mouser and this is the cap specified. Should I reorder the the lower voltage caps?
Click to expand...

NO, They are FINE.... you missed my response above^^^^^


word to the wise, bisonguy - see what you could have $$ started? :D I always gotta be careful with things like that....
 
Bisonguy Mark had previously helped on another problem i had but not this. I believe he was ribbing you for making me think what i had wasn't the correct part and thinking i would need to spend money and order new ones. Thanks to both of you for your help.
I will keep this thread going as i have many more questions (transistors, pots, bypass filters, etc.) about the rebuild but want to take things one step at a time. For now it is getting all caps replaced. Josh
 
bisonguy said:
Point taken Mark. I didn't realize you had already been helping him.
Click to expand...

wrong point, your help was WELCOME!!! Didn't mind you jumping in one iota... that's why the
Excellent answer, well covered, couldn't have said it better myself
Click to expand...
response - an honest and admiring assessment.... hoped it would be positive feedback and encouragement to do more...

sort of proof that the "teaching to fish" was working here....

point was the question about the 250v cap, gotta ask yourself - will idle curiosity scare someone who was unsure and just following a list into wondering if the list was valid.

ask about where his parts choices came from. research the source. Don't sweat it, i.e. what you asked, I'm just trying to share my long experience coaxing the unsure and hesitant through the maze...

and I honestly can't recall (and didn't research my old posts, which I usually do) if I supplied the list to him or he found it himself...
 
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markthefixer said:
I honestly can't recall (and didn't research my old posts, which I usually do) if I supplied the list to him or he found it himself...
Click to expand...


I found it myself. I have been following along with alot of the builds and finally decided now was the time. I looked at the list supplied to Hoodcom and Kingbubba and ordered away. Hind sight I should have checked that the list was up to date but what can you do now, live and learn. Again I will have many questions to ask as I continue on with my build and will be trying to learn as much as possible along the way. Thanks for both of you being willing and able to "steer, work the gas and brake"
 
Alright I have hit a speed bump. I had some of the foil lift on one connection and am unsure what action I should take. I was thinking I could place a jumper between the two caps as represented in my picture. Is this the way I should handle the problem?

untitled.jpg
 
You try to put the foil back, and then clean the green paint off of it, and add the bare wire jumper soldered on the length of it, with the jumper and the component joints forming the strength to hold it in place.
 
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I found that the BOM I placed my order from only shows 2 caps for the filter amp (C3& C6). When looking at it there are actually 4 on that board, (C9&C12) which are also 4.7/25 & 10/25. What i'm wanting to know is would it be ok for me to use radio shack electrolytics in those two locations. They are xicon 4.7/35 & 10/35 +-20% -40 to +85c. Thanks
 
Alright Electrolytic caps are done so I would like to move on to the next step in my rebuild. I have done a lot of reading and see several things that are recommended for a complete restore.

1. Reapplying the heatsink grease. Do I just remove the old ones clean with wd-40 apply enough grease to cover and reapply? Does it get applied to both sides of the insulator? Do I need to remove the heatsinks or just access from the outside.
2. Do I need to order the extras from the list that is here? I pulled the list from Kingbubba’s latest update but believe I need to add two “VR1 500 ohms 12 turn offset pot 652-3266P-1-501LF” using the two “52-3386H-1-502LF” in this list as the bias pots?
3. Will this be everything recommended? Or do I need to locate the relays I have seen mentioned somewhere?

Thanks again for the help, Josh


AWR- 106
Q9, Q12 35V 2SD325R-E to-220 512-KSC2073TU_Q to-220
Q10, Q13 50V 2SC945A-R to-92 512-KSC2310YBU to-92
2 Q3, Q11 50V 2SC945A-R to-92 512-KSC1845UBU to-92
D5 6.1V .5W ZENER 512-1N5234B 6.2V
3 D2, D6, D4 1S2473 512-1N4148
Q4 50V 2SC1384-R to-92 512-KSC2690AYS to-126
Q8 50V 2SA684A-R to-92 512-KSA1220AYS to-126
Q1 60V 2SD313P-E to-220 512-KSC2073TU_Q to-220
Q2 160V 2SC869-D to-92 512-KSC2310YBU to-92
2 D1, D3 24V 5W ZENER 512-1N5252B 24V
2 VR1,VR2 5KOHM 1 TURN. 652-3386H-1-502LF
Q5 60V 2SB507P-E to-220 512-KSA940TU_Q to-220
Q6 25V 2SA628A-D to-92 512-KSA1013YBU to-92
Q7 50V 2SA720-R to-92 512-KSA992FBU to-92
 
bdblkta said:
I found that the BOM I placed my order from only shows 2 caps for the filter amp (C3& C6). When looking at it there are actually 4 on that board, (C9&C12) which are also 4.7/25 & 10/25. What i'm wanting to know is would it be ok for me to use radio shack electrolytics in those two locations. They are xicon 4.7/35 & 10/35 +-20% -40 to +85c. Thanks
Click to expand...

NO, 3 & 6 are one channel, 9 & 12 are the other channel -- want a lopsided sounding system? I don't know how that got past all my checks...

bdblkta said:
Alright Electrolytic caps are done so I would like to move on to the next step in my rebuild. I have done a lot of reading and see several things that are recommended for a complete restore.

1. Reapplying the heatsink grease. Do I just remove the old ones clean with wd-40 apply enough grease to cover and reapply? Does it get applied to both sides of the insulator? Do I need to remove the heatsinks or just access from the outside.
2. Do I need to order the extras from the list that is here? I pulled the list from Kingbubba’s latest update but believe I need to add two “VR1 500 ohms 12 turn offset pot 652-3266P-1-501LF” using the two “52-3386H-1-502LF” in this list as the bias pots?
3. Will this be everything recommended? Or do I need to locate the relays I have seen mentioned somewhere?

Thanks again for the help, Josh


AWR- 106
Q9, Q12 35V 2SD325R-E to-220 512-KSC2073TU_Q to-220
Q10, Q13 50V 2SC945A-R to-92 512-KSC2310YBU to-92
2 Q3, Q11 50V 2SC945A-R to-92 512-KSC1845UBU to-92
D5 6.1V .5W ZENER 512-1N5234B 6.2V
3 D2, D6, D4 1S2473 512-1N4148
Q4 50V 2SC1384-R to-92 512-KSC2690AYS to-126
Q8 50V 2SA684A-R to-92 512-KSA1220AYS to-126
Q1 60V 2SD313P-E to-220 512-KSC2073TU_Q to-220
Q2 160V 2SC869-D to-92 512-KSC2310YBU to-92
2 D1, D3 24V 5W ZENER 512-1N5252B 24V
2 VR1,VR2 5KOHM 1 TURN. 652-3386H-1-502LF
Q5 60V 2SB507P-E to-220 512-KSA940TU_Q to-220
Q6 25V 2SA628A-D to-92 512-KSA1013YBU to-92
Q7 50V 2SA720-R to-92 512-KSA992FBU to-92
Click to expand...

sigh - THERMAL TRANSFER COMPOUND is for filling gaps between insulator and transistor, there are TWO sides to an insulator - why wouldn't one side not have gaps? You don't want to use too much - if there's squeeze out it should be minimal to none.

you will need to access the underside - because when the transistors are out, the sockets are adrift AND they have to be CAREFULLY positioned when reassembling - there are indentations in the heatsink that the socket fits into, miss them and the socket will break when you tighten down - and then they could also short to the heat sink. after installation you HAVE TO ohmmeter check for short circuits to the heat sink from ALL three transistor connections - the two pins and the case of the transistor.
with all this in mind, if you can do it without pulling them, sure...


yes on the pots - they are essential in the amp.

yes on the relay, 653-my4-02dc24 at mouser.

this is why I ask for the list to be published before any ordering is to be done.
 
markthefixer said:
sigh - THERMAL TRANSFER COMPOUND is for filling gaps between insulator and transistor, there are TWO sides to an insulator - why wouldn't one side not have gaps? You don't want to use too much - if there's squeeze out it should be minimal to none.
Click to expand...


Sorry for the incorrect terminology I saw it referred to as grease in another thread and went with it as i couldn't recall the name. But I did at least order the correct stuff from a thread where you had mentioned it.
Is the correct way to clean this off with the wd-40?

So the extra parts listed and the relay are all that I need for a complete rebuild? I had already ordered and installed the four large caps.

Thanks again Mark. I really am trying to learn from you.
 
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Alright I have imported the remaining parts into the BOM and I am coming up with these errors. Hate to ask but could someone please help me out here? Thanks for your help

No Match Found For 512KSC1845UBU to92
Search for Product

More Than 1 Match Found for 512KSC2690AYS to126
Select from a list of matching products

More Than 1 Match Found for 512KSA1220AYS to126
Select from a list of matching products

No Match Found For 512KSC2073TU Q to220
Search for Product

No Match Found For 512KSA940TU Q to220
Search for Product
 
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bdblkta said:
Alright I have imported the remaining parts into the BOM and I am coming up with these errors. Hate to ask but could someone please help me out here? Thanks for your help

No Match Found For 512KSC1845UBU to92
Search for Product

More Than 1 Match Found for 512KSC2690AYS to126
Select from a list of matching products

More Than 1 Match Found for 512KSA1220AYS to126
Select from a list of matching products

No Match Found For 512KSC2073TU Q to220
Search for Product

No Match Found For 512KSA940TU Q to220
Search for Product
Click to expand...

512-KSC1845EBU
512-KSC2690AYS
512-KSA1220AYS
512-KSC2073TU
512-KSA940

a few of these were just missing the dash.
 
Alright now I am at a loss. I have been trying to figure out how to correctly install the transistors. Do I just intall them as they were previously? I have read a few things talking about ECB and such but I don't really understand. Thanks for any help, Josh
 
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