Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

16B chassis — questions
#35

The 16b chassis that I pulled from the attic is missing the two electrolytic cap cans at the rear (#87 & #88) and there are a few (3?) stray wires as well.  

The attached pic shows the current situation.

   

Green arrow points to the lead from the center tap of the power transformer.  This is 400 volts, correct?  

My understanding is that this goes to the two cans at the rear and then to #75 (10 uF, 50v).

1.  Does this lead go to the center terminal of the cans or to the outside?  For all three cans?  Or is the wiring reversed for #75 (pos. chassis ground)?  Are there jumpers to make the connection (in an original set)?

White arrow points to two leads running from two side tabs on bakelite cap. #86.  One has a terminal (not shown); the other appears to have been cut.

2.  Same question as above:  In an original set do these go to the center terminal of the cans or to the case?  What is the polarity? (Positive? Because the center tap on the xfrm is negative?)

3.  Since the cans are supposed to be insulated from the chassis, I assume that this is the reason that the neg. chassis ground on #87 & #88 does not short with the positive chassis ground on #75 -- or am I all wet?

Red arrow points to a cap (value unknown) that appears to have been retrofitted at some point in the past.  This appears to be wrong for  a number of reasons:  (a) it does not conform to any part of the schematic for #87 or #88, which are connected to the center tap of the transformer and not to the resistor #81; (b) if it is a replacement for cap #75, it should be positive-grounded to the chassis.

I am assuming that the bottom-most tap on the voltage divider resistor #81 is not grounded (because is is offset by a fiber/felt washer). 

4. Is the string of resisitors (#81-84 and #91) what creates the voltage drop from 400 v at the transformer to 50 v at cap #75?

Finally, bakelite cap #86 (nominally 0.3 uF per the schematic) appears to be made in internally of two 0.15 caps that are wired in parallel by a jumper between the end terminal and the middle terminal, correct?

5.  If I want to use two caps instead of a single 0.3 uF as a replacement (i.e., keeping the jumper and the outward appearance), which terminal has the common end of the two caps?  It seems that it should be terminal nearest the mounting lug (i.e., the one without the jumper from the end terminal), but can anyone confirm this?

I want to retain the original appearance as much as possible but will probably use a terminal strip for #87 and #88 until I can find replacement cans to restful and mount (is that what Kutztown is for?).  Happy to post pics/notes when this phase is done.  

This site is a fabulous resource!!!

Cheers and Happy New Year,

Matthew W. Woodruff


Messages In This Thread
17b chassis — newbie questions - by mwoodruff - 12-20-2018, 09:24 AM
RE: 17b chassis — newbie questions - by morzh - 12-20-2018, 10:37 AM
RE: 16B chassis — questions - by Radioroslyn - 12-27-2018, 03:36 PM
RE: 16B chassis — questions - by mwoodruff - 12-27-2018, 05:15 PM
RE: 16B chassis — questions - by Radioroslyn - 12-27-2018, 06:08 PM
RE: 16B chassis — questions - by mwoodruff - 12-28-2018, 07:59 AM
RE: 16B chassis — questions - by Radioroslyn - 12-28-2018, 12:17 PM
RE: 16B chassis — questions - by mwoodruff - 12-31-2018, 12:39 PM
RE: 16B chassis — questions - by mwoodruff - 12-31-2018, 01:22 PM
RE: 16B chassis — questions - by Radioroslyn - 12-31-2018, 02:31 PM
RE: 16B chassis — questions - by mwoodruff - 01-07-2019, 02:03 PM
RE: 16B chassis — questions - by EdHolland - 01-07-2019, 05:39 PM
RE: 16B chassis — questions - by mwoodruff - 01-08-2019, 08:47 AM
RE: 16B chassis — questions - by mwoodruff - 01-08-2019, 12:35 PM
RE: 16B chassis — questions - by Radioroslyn - 01-08-2019, 01:35 PM
RE: 16B chassis — questions - by mwoodruff - 01-25-2019, 06:43 PM
RE: 16B chassis — questions - by Radioroslyn - 01-25-2019, 08:15 PM
RE: 16B chassis — questions - by mwoodruff - 02-22-2019, 02:17 PM
RE: 16B chassis — questions - by mwoodruff - 02-22-2019, 04:02 PM
RE: 16B chassis — questions - by mikethedruid - 02-22-2019, 05:21 PM
RE: 16B chassis — questions - by mwoodruff - 03-07-2019, 01:28 PM
RE: 16B chassis — questions - by EdHolland - 03-07-2019, 03:58 PM
RE: 16B chassis — questions - by amptramp - 03-08-2019, 09:08 AM
16b power supply questions - by mwoodruff - 12-26-2018, 12:36 PM
RE: 16b power supply questions - by Radioroslyn - 12-26-2018, 01:41 PM
16b filter bank capacitor voltages - by mwoodruff - 12-26-2018, 03:04 PM
RE: 16b restoration questions - by klondike98 - 12-26-2018, 04:51 PM
RE: 16b restoration questions - by morzh - 12-26-2018, 06:10 PM
RE: 16b restoration questions - by amptramp - 12-26-2018, 06:26 PM
RE: 16b restoration questions - by Radioroslyn - 12-26-2018, 08:41 PM
RE: 16b restoration questions - by mwoodruff - 12-27-2018, 11:55 AM



Users browsing this thread: 20 Guest(s)
[-]
Recent Posts
Philco 46-420 Code 121 Reception issues
You mentioned the Philco manual and going through the check points...just to be sure we're on the same page here's the m...klondike98 — 08:13 PM
Philco 42-1008 conversion kit
Interesting. I haven't seen that before.klondike98 — 07:02 PM
12' Philco
Yes I had looked for it on the web as well some time back and could not find it. I was glad to see it turned up in Ron'...klondike98 — 06:59 PM
Shadow Meter Bulb
Now if you had a set with a tuning light then the bulb type is important to the circuit, some sets used those prior to t...Arran — 04:58 PM
Shadow Meter Bulb
Ok. Thanks for the correction.RossH — 03:09 PM
Model 28L
For 28 you will probably need to buy a Hammond 125CSE. Or any of the series of the power you need, with SE suffix. Then ...morzh — 02:09 PM
37-60 revision 6
I am restoring a Philco 37-60 and it shows run 6 they removed the ground from G3 of the 6K7G and put the G3 to -2.5v for...bobbyd1200 — 01:01 PM
Shadow Meter Bulb
Mike is correct on the bulb connection, two separate circuits. I found that by rotating the bulb and sliding it forward ...RodB — 12:19 PM
Hickok AC51 tube tester
Cleaned ann contacts, switches and sockets, works great now.martinj — 11:32 AM
Model 28L
Hello, I'm restoring a Philco 28L and the output transformer is open. Part number of the transformer is 32-7020. Can...HORSTE — 10:32 AM

[-]
Who's Online
There are currently no members online.

>