some help with resistance readings [resolved]

[Marks World]

Hi All,

Well, 7 years later I finally got around to building my Eros.  Thus this question relates to Rev 5.19.09 according to the manual cover.

I've finished assembly and carefully inspected all joints and connections.  All looks fine, I double-checked each of the connection points as assembling and also as I finished every second page since I don't have anyone else that can look at it for me.

I'm now running through the resistance levels.  Here is what I am getting on the terminal strips.
1 0
2 85K
3 0
4 75k
5 0
6 473k
7 474k
8 0
9 46k
10 46k
11 0
12 75k
13 0
14 85k
15 0
16 No connection
17 No connection
18 0
19 47k
20 through 26 all 0
27 47k
28 0
29 and 30 no connection

Terminals 2, 4, 9, 10 12, and 14 are all quite a bit more than 10% above the values stated in the manual.  Are these still within acceptable amounts?

Thank you for any help, this is my first kit assembly so I'm hoping for a good outcome.  :-)

Regards, Mark

[Paul Birkeland]

Slightly high resistances make one suspicious of a possible soldering issue (maybe on the ground buss), so it's worth looking at all the joints where black wires connect to be sure they are all solid.

[Marks World]

Thanks, I looked over and checked the conductivity between each connector for the bus bar.  Nothing out of the ordinary.  I will try reflowing the solder on each connection on the Ground bus bar.

[PS2500]

Time flies, don't it?

I see that I've clocked 7 years with my own Eros. Solidarity! I'm happy to know that if that's a record, I'm only a joint holder. Mine's the tape version. I finished it a few months ago but I put it aside for later when the resistances didn't check out. Other projects, and all that.

I haven't seen any solder problems yet so I'll probably have to ask Doc B or Paul what to hunt for. The Eros tape forum is very low-activity. Everyone who bought one before it was discontinued probably finished a long time ago.

[Marks World]

Time flies, don't it?

I see that I've clocked 7 years with my own Eros. Solidarity! I'm happy to know that if that's a record, I'm only a joint holder. Mine's the tape version. I finished it a few months ago but I put it aside for later when the resistances didn't check out. Other projects, and all that.

I haven't seen any solder problems yet so I'll probably have to ask Doc B or Paul what to hunt for. The Eros tape forum is very low-activity. Everyone who bought one before it was discontinued probably finished a long time ago.

lol, Well, I can't offer much in way of technical support, but I'm glad I could provide some moral support! 

[Marks World]

Slightly high resistances make one suspicious of a possible soldering issue (maybe on the ground buss), so it's worth looking at all the joints where black wires connect to be sure they are all solid.

I've checked each connection and reflowed the solder on each black wire connection, then pulled with the needlenose on each wire to see if i spot any weak connections or where I may have nicked a wire by accident.  All seems fine.  Also double checked the values of the resistors running between the but bar and the other terminals. 

I noticed another post on the forum that someone had slightly higher resistance but someone responded that those were within tolerance.  Could that be the case here?  I list below only the ones that are higher than expected.  The first number is the terminal or tube pin number, the second is the listed expected value per the manual, and the third is my own reading.

T2 71k ohms 85k Ohms
T4 60k Ohms 75k Ohms
T9 39k Ohms 46k Ohms
T10 39K Ohms 46K Ohms
T12 60K Ohms 75K Ohms
T14 71K Ohms 85k Ohms

A6 60K Ohms 75K Ohms

B6 60K Ohms 75K Ohms

C1 39K Ohms 46K Ohms
C2 60K Ohms 75K Ohms
C6 39K Ohms 46K Ohms
C7 60K Ohms 75K Ohms

[Paul Joppa]

I notice that these resistances are all very close to 20% high. Makes me want to check whether the meter is accurate ... Probably worth checking against a known resistor just to be sure. We have more than once seen this happen with depleted batteries in the meter ...

[Marks World]

I notice that these resistances are all very close to 20% high. Makes me want to check whether the meter is accurate ... Probably worth checking against a known resistor just to be sure. We have more than once seen this happen with depleted batteries in the meter ...

Thank you for the suggestion.  I did a test against a wire wound resistor and I have two different meters.   The test was spot on and both meters are reporting the same.  In addition, other pins are ok, Such as Terminals 27 and 19 are to be 47k and both of those are spot on.

I've been creating a spreadsheet to backtrack every connection (also to double check that nothing is connected in the wrong spot, but I've already done that step by step so I don't think so) and I notice on T4, T9, 10 and 12 the values all correspond to a single resistor, T4 75k  is a match to the resistor between T4 and T1 (75K), T9 at 46k is close to the 47K  between T9 and T24, T10 at 46k is close to the resistor of 47k between R10 and T25, and T12 at 75K  is close to the 75k between T12 and T15. 

T2 and T14 I have values of 85k, but I notice both of these appear to put 10.5k resistors in series with Terminals T4 and T12 both of which of course have readings of 75k.  So I think I can rule out anything at T2 and T14 as the culprits.

Any other insights would be welcome.  Thanks for any help

[Marks World]

Thank you for the suggestion.  I did a test against a wire wound resistor and I have two different meters.   The test was spot on and both meters are reporting the same.  In addition, other pins are ok, Such as Terminals 27 and 19 are to be 47k and both of those are spot on.

I've been creating a spreadsheet to backtrack every connection (also to double check that nothing is connected in the wrong spot, but I've already done that step by step so I don't think so) and I notice on T4, T9, 10 and 12 the values all correspond to a single resistor, T4 75k  is a match to the resistor between T4 and T1 (75K), T9 at 46k is close to the 47K  between T9 and T24, T10 at 46k is close to the resistor of 47k between R10 and T25, and T12 at 75K  is close to the 75k between T12 and T15. 

T2 and T14 I have values of 85k, but I notice both of these appear to put 10.5k resistors in series with Terminals T4 and T12 both of which of course have readings of 75k.  So I think I can rule out anything at T2 and T14 as the culprits.


I've tried attaching my spreadsheet below
Any other insights would be welcome.  Thanks for any help

I spotted an error in the spreadsheet, on T12, it shows as connecting a 10.5K resistor to T13, which is wrong, it is actually T14.  I wired it correctly but the spreadsheet is wrong.

[Paul Joppa]

I dug out my notes from 2008/2009 when the kit was first released, and looking at the schematic your resistances are correct. In the course of checking up, I found this post from 2010:

https://forum.bottlehead.com/index.php?topic=367.0

This complication persisted in the 2013 manual. I don't know how it came to slip past us without even a sticky note in the forum.

[Marks World]

I dug out my notes from 2008/2009 when the kit was first released, and looking at the schematic your resistances are correct. In the course of checking up, I found this post from 2010:

https://forum.bottlehead.com/index.php?topic=367.0

This complication persisted in the 2013 manual. I don't know how it came to slip past us without even a sticky note in the forum.

Thank you so much Paul, I know I'm not that experinced, but as I was now mapping things out I couldn't figure out how the readings could be wrong.  I thought it was my lack of knowledge.  Now onto voltage checking!   

How do I change the title of the topic to say "resolved"