Intermittant response from spectrum analyzer

Question

I have LabVIEW 8.2, NI 488 v.52. I am having problems talking to an old HP 8568A spectrum analyzer. 
I can write to it OK, but reads are intermittant. 
It takes a carriage return on the end of commands. On some reads, the response is fine using VISA in LabVIEW or using the NI-488.2 communicator, but on other reads, I get a timeout error EABO.
The funny thing is, the response is actually there from the analyzer...It's like VISA or LabVIEW isn't seeing the response every time.  And this happnes with every command written to the analyzer that generates a response..
Here is the NI-SPY capture where the first read went perfectly:
2.  ibrd(UD0, "-13.50..", 2000 (0x7D0))
Process ID: 0x000008A8         Thread ID: 0x00000F1C
Start Time: 22:10:05.664       Call Duration 00:00:00.010
ibsta: 0x2900       iberr: 0             ibcntl: 8(0x8)
Here is another where the read timed out, but the correct response was actually read:
>8.  ibrd(UD0, "-13.50..", 2000 (0x7D0))
>Process ID: 0x000008A8         Thread ID: 0x00000F1C
>Start Time: 22:11:41.672       Call Duration 00:00:16.774
>ibsta: 0xc900       iberr: 6             ibcntl: 8(0x8)
Thanks in advance for your time and help.
Viv

Answer 1

ALSO:
I forgot to mention that we ended up with the HP8568A having to specify the to specify the number of characters that were read on each read request in the VISA Read VI due to the 8586A’s not sending an EOI.
The read request would time out if we requested the read to end on an EOS character. 
Viv